His most successful creation was the occult investigator Jules de Grandin, who featured in over ninety stories published between 1925 and 1951 (including a novella, The Devil's Bride). Night Shade Books republished all the stories in a five volume set called The Complete Tales of Jules de Grandin.
After Mr Quinn's death, many of the de Grandin stories were put out in mass-market paperback compilations from Popular Library in the early 1970s, but reprints were never done, and recent collections of his work have been in much smaller runs by independent publishers. A few of his stories have entered the public domain and can be found with searching, and many individual stories have been reprinted in various horror and weird fiction anthologies.
Seabury Quinn's work provides examples of:
- Artistic License – Physics: The description of radium interacting with electricity in "The Chapel of Mystic Horror" just doesn't make sense— perhaps Quinn misunderstood the electroconductive properties of radium.
- Assassin Outclassin': In The Heart of Siva, four thuggee assassins had targeted a dance troupe for blasphemy. They had already murdered a few members and were going to try again, but this time de Grandin had been targeting them and he murders three of them in the dark with his kukri. One poor assassin even gets disemboweled and slowly died squealing.
- Badass Boast: de Grandin makes several, but the one in "The Corpse-Master" is one of his best (see below).
- Big Eater: Sometimes it seems like one of the things Jules de Grandin values most about his friendship with Dr. Trowbridge is access to Dr. Trowbridge's excellent cook.
- Blood Knight: de Grandin loves fighting evil people and he sometimes gets a disturbing grin at the prospect of putting down a villain. He sometimes even turns down cases initially, because he was bored that they sounded like a generic crime. Trowbridge notes to himself that de Grandin is a natural killer in The Devil's Bride.
- Brainwashed and Crazy: "The Brain-Thief". A pair of young couples had inadvertently offended an East Indian mystic who had powerful hypnotic powers. In revenge, he caused the husband of one pair and the wife of another to fall madly in love and divorce their original spouses. After two years of marriage and a baby, the hypnosis was deliberately ended causing the two wonder what happened to their spouses, why they're with someone else and why is there a baby. This drove the woman to commit suicide and take the baby along with her.
- Captured by Cannibals: "The Isle of Lost Ships" where a half-breed Malay prince and his tribesmen were luring ships to their doom and their crew to the village cooking pots.
- Challenge Seeker: Jules de Grandin is the world's greatest criminologist. However because it's so easy for him to solve mundane crime, he refuses to take standard criminal cases and only accepts jobs that appear to involve the occult. In most stories where he's doing an ordinary murder case, it's either he got involved by coincidence or the police were too stumped and the stakes are very high.
- Damsels in Distress: Plenty! Many stories feature someone's wife or girlfriend being threatened by some kind supernatural menace, including "The Bride of Dewer" where an old Saxon god tries to get Droit du Seigneur with a new bride.
- Deal with the Devil: In "The Bride of Dewer" a family is cursed since an ancestor committed the following crime: The ancestor was a knight in the crusades and his small band were wiped out while more enemies kept pouring out. At first he called out for help from saints and God, but when there was no help - he renounced his faith and called on the gods of his Saxon heritage, offering anything they wish for their aid. Dewer, the god of the wild hunt, appears and slaughters the enemies, in return he has his way with the bride of every male descendant of the knight until someone breaks the curse.
- Due to the Dead: In Satan's Stepson, the villainous Dr. Sun Ah Poy is dying after turning on the evil Konstantin. de Grandin's friend Renouard salutes Dr. Sun as Dr. Sun was once a friend and comrade of Renouard's, while de Grandin salutes because Dr. Sun told him where Konstantin was hiding.
- Early-Installment Weirdness: Some of the earliest Jules de Grandin stories had Trowbridge go overseas and seeing de Grandin (this happened in "The Isle of Lost Ships" and "The Tenants of Broussac") working for the government or wealthy individuals and companies. Also de Grandin used to be a bit of a Punch-Clock Hero and would sometimes pocket fees and cash rewards from those he helped.
- Expy: Jules de Grandin is pretty much Abraham van Helsing with a soupçon of Hercule Poirot.
- Experienced Protagonist: Jules de Grandin was already world famous as a global leading figure in criminology, military intelligence, medicine, science and occult matters. The first time Trowbridge encounters de Grandin, he's amazed at the opportunity of meeting this legendary man.
- Even Evil Has Standards: In Satan's Stepson the evil Dr. Sun Ah Poy who showed up in the earlier story The Lost Lady, is quick to abandon his ally Konstantin and go warn de Grandin, once Dr. Sun finds out that Konstantin is a demonic "callicantzaros". de Grandin explains that even though Dr. Sun is a very bad man, he's Chinese and the Chinese fear and hate demons.
- Eye Scream: de Grandin drops the kids gloves in The Devil's Bride. In retaliation for the crucifixion of a woman under his protection, the blinding and mutilation of an innocent girl, the death of a recurring policeman and the murder of a child. de Grandin gives Vladimir Bazarov an ugly death. He first skewers out one eye and then he stabs out the other, then he cuts up Vlad's face before stabbing his sword-stick through Vlad's mouth.
- Fanservice: In the Night Shade Book editions, the foreword mentions the reason why Damsel in Distress feature so often is that the owner of Weird Tales believed covers with a nude woman sold best and so Seabury Quinn would include women in various states of undress in his stories. Also, getting the cover story meant a bigger paycheck for the author.
- Five Rounds Rapid: The Jules de Grandin stories were perhaps most famous for having de Grandin gun down a werewolf without any silver bullets in "The Blood-flower". This was one of the earliest incidences where modern technology could defeat a supernatural being on its own. Interestingly, unlike the usual way this plays out, de Grandin didn't use a BFG of any kind. Instead he had his little automatic pistol with him and he fired 8 rounds into the werewolf in a tight pattern, leaving a hole "big enough to walk through" when all the bullets hit. To be fair, the werewolf was a skinny old man and he gained his lycanthropy through experimenting with blood-flowers, rather than curse or Deal with the Devil.
- Funetik Aksent: Throughout various stories.
- The Gadfly: Jules de Grandin has a mischievous streak and it really comes out whenever he meets someone he finds annoying.
- God Is Good: Jules de Grandin often makes use of charms and incantations that invoke the power of God to banish demons and other supernatural threats. In "The Gods of East and West", de Grandin states that the Great Spirit is merely another identity of God and the appropriate incarnation to appeal to in that instance and indeed, the Great Spirit physically manifests itself to smite Kali.
- Golem: In "Stoneman's Memorial", an embittered soft-drink maker has a memorial with nude marble statuary built in a slum. The man is also the only remaining person in the world to know a spell that'll bring statues to life and he uses this to make his statues hunt and kill prostitutes.
- Good Hurts Evil: The de Grandin stories are full of these, including one where de Grandin and a priest destroy an evil cult just by praying in front of them. Justified by de Grandin in that evil gods and spirits are just Tulpa that accumulated power through belief. de Grandin believes that God is real and so invoking that power it's easy to smite evil - that and because centuries of belief in exorcism has given it real power.
- Good Is Not Nice: In the short story "The Brain-Thief", Jules de Grandin had already chopped off the hand of the East Indian hypnotist (this is justified as the villain was about to shoot a cop). He then grabs the helpless villain and executes him by shoving his face into a hot stove. In the "The Wolf of St.Bonnot", an annoying woman interrupted a dangerous seance that de Grandin had to hold and so Jules threatened to kill her with a knife that he earlier used to kill an ectoplasmic werewolf spirit.
- Guile Hero: Jules de Grandin is a very cunning man and oftens puts his enemies at a disadvantage through trickery. In one instance, he uses Trowbridge to distract a villain while he puts a small dripper of fluorescent paint under the car. This allowed the heroes to follow the villains without them noticing.
- Half-Breed Discrimination: The villain's motivation in "The Isle of Lost Ships".
- Hollywood Voodoo: "The Drums of Damballah" does avoid the usual Voodoo Doll business, but also has Human Sacrifice and the use of an inverted cross.
- I Ate WHAT?!: In "The Isle of Lost Ships", de Grandin and Trowbridge are most displeased to find that they had been eating "long pig" at the dinner table of Goonong Besar.
- I'm a Humanitarian: "The Isle of Lost Ships" by way of degenerate island tribal cannibals, while "Children of Ubasti" had a race of cat people play Hunting the Most Dangerous Game involving kidnapped women and eating them afterwards. In both senses of "I'm a humanitarian" there's the "The White Lady of the Orphanage" where a kindly matron of an orphanage is also addicted to eating children.
- Immune to Bullets: Averted in many cases, while there are supernatural things that couldn't be gunned down because they're immaterial or already dead, many supernatural beings can be done in with a well-aimed gunshot. In The Thing in the Fog, de Grandin explains the reason for the silver bullet myth was that guns back in the day were very weak and silver was harder bullet material than lead, so werewolves should be shot with silver to pierce their hides.
- Killer Gorilla: They show up in several de Grandin stories, including his very first one 'Horror on the Links'. In an added bonus, the gorilla in that story can turn human courtesy of his Mad Scientist owner!
- Kill It with Fire: Fire purifies and de Grandin has used that to destroy cursed artifacts and ghosts including a spirit he first caught with a vacuum cleaner before tossing it in a furnace.
- Kissing Cousins: A young man falls in love and marries his first cousin in "The Jest of Warburg Tantavul". The marriage is actually celebrated in the community, too bad it turns out they're not cousins.
- Kryptonite Factor: In "The Devil's Rosary", de Grandin deduced that if the Tibetan priests could turn invisible and cast lightning and hurricane winds with ease, then why hadn't they conquered China. He then consults with a Chinese friend of his and discovers that the air magic used is easily dispelled by chicken blood. de Grandin uses that to stop the would-be assassin. Many other stories involving the supernatural involves using Kryptonite Factor against them.
- Mad Doctor: A couple, but the one in "The House of Horror" rates special mention he was a bone specialist who's son committed suicide after getting rejected by a beautiful girl. So he went and tortured women by removing the bones out of their bodies while keeping them alive, he even surgically melded them together into one gigantic monstrousity.
- Majored in Western Hypocrisy: The villain in "The Isle of Lost Ships".
- Money, Dear Boy: In the 3rd Nightshade books "The Dark Angel", the preface mentions how Seabury Quinn was unapologetic about writing the de Grandin stories for money. While Robert E. Howard was a big fan of Quinn, Lovecraft decried the attitude saying the stories had nothing of Quinn in them (note that Lovecraft actually liked Quinn and had high opinion of him as a person).
- The Mourning After: See Tragic Monster below.
- Occult Detective: Jules de Grandin. Among his varied illustrious careers, he was a criminologist in France, and through academics, experience and fieldwork - he's an expert in all the occult traditions of the world.
- Omnidisciplinary Scientist: He's a medical professional but he's also a master in other fields of science such as chemistry, botany, anthropology and etc.
- Officer O'Hara: Not surprising, given the time period many of the stories were written in; Sergeant Jeremiah Costello, in particular, shows up in several stories.
- Old Shame: For Seabury Quinn, it would be the story "The Black Moon" where Jules de Grandin enlists the KKK to lynch members of a voodoo cult. After that low-light, the stories would do a better job of depicting other races and religions.
- Our Monsters Are Different
- Our Ghosts Are Different: If blessed hawthorne and prayer doesn't dispel them, try radium salts to disrupt their electromagnetic resonance! (Note: the story this occurs in, "The Chapel of Mystic Horror", predates Ghostbusters by
over half a century!) - Our Vampires Are Different: The whole Wooden Stake thing? Averted, at least in "The Man Who Cast No Shadow". On the other hand, "Restless Souls" goes with more traditional vampirism (must be invited in, fears holy relics, etc.).
- Our Werewolves Are Different: Some are created by curses ("The Gentle Werewolf"), some by pacts with infernal powers ("Uncanonized"), some by accident ("The Blood Flower") and some by deliberate infection ("Bon Voyage, Michele"). And enough large-caliber shots will take one out regardless of the bullets' metal content (in "The Blood Flower")...
- "The Wolf of Saint Bonnot" is a ghost (yes, Our Ghosts Are Different this time too) who induces lycanthropic madness in others.
- Our Ghosts Are Different: If blessed hawthorne and prayer doesn't dispel them, try radium salts to disrupt their electromagnetic resonance! (Note: the story this occurs in, "The Chapel of Mystic Horror", predates Ghostbusters by
- Our Vampires Are Different: In The Malay Horror, de Grandin goes up against a Penanngalan - a Southeast Asian blood-drinking undead that pops out of its own corpse and flies around as only a head trailing its stomach and lower intestine.
- Past-Life Memories: The driving plot element in Alien Flesh.
- Pay Evil unto Evil: If you kill innocents around de Grandin, he will gladly kill you in as brutal a fashion as possible.
- Poirot Speak: Jules de Grandin, mais oui! Sometimes other characters as well.
- Philosopher's Stone: In "The Devil's Rosary", it's the property of Tibetan Buddhist sorcerer-monks which they use to make gold statues and they're willing to kill to defend it.
- Post Modern Magic: de Grandin defeats a spirit that had become too solid to affect with holy water and too immaterial to shoot...by sucking it up in a vacuum cleaner.
- Rage Against the Heavens: In The Devil's Bride, Grigor and Vladimir Bazarov were Roman Catholic priests in the Soviet Union. When they were taken and tortured for their beliefs, they quickly joined anarchists and became willing agents for the Soviet Union to create the unholy, anti-religious alliance, the Union of the Militant Godless as a means to destroy Christianity.
- Reincarnation Romance: "Ancient Fires", "The Globe of Memories"
- Religion of Evil: Of all things, it's Tibetan Buddhism in "The Devil's Rosary". There the practitioners are depicted as really being devil worshippers of Satan in his incarnation as the Prince of Air. And with that they can turn invisible and control lightning and hurricane-level winds. Besides that, there are plenty of cults and evil religious devotees to fight, including ghosts of the Knights Templar of Cyprus who worship the goddess Cytherea in "The Chapel of Mystic Horror"
- Scaled Up: "The Tenants of Broussac" where the ghost of a debauched nobleman was cursed to take on the form of a snake.
- "Scooby-Doo" Hoax: A few (titles omitted for spoiler purposes); zigzagged in one story. "The Doom of the House of Phipps"
- Science Marches On: "Terror on the Links" asserts that only chimpanzees, of the large primates, are capable of tool manipulation with their opposable thumbs; subsequent decades of primatology have shown otherwise. It also assumes gorillas are the most aggressive and dangerous of apes.
- The Scully: Dr. Trowbridge, who you think would be more inclined to believe de Grandin's theories after a few adventures. ("The Silver Countess" is a particularly good example of this.)
- Secretly Wealthy: Both Jules de Grandin and Trowbridge appear to be moderately wealthy because of their prominent medical jobs. In actuality, they're much wealthier than that having taken lots of gold and gems from a pirate's treasure trove. Costello also has a huge nest-egg for himself as he was also one of the men to loot that pirate's hoard. This means that the three of them work more for helping people and solving mysteries than making a living (earlier Jules de Grandin stories had him earning fees and collecting rewards).
- Shared Universe: The Jules de Grandin universe is linked with the world of Manly Wade Wellman's heroes such as Judge Pursuivant and John Thunstone. In the Black Moon omnibus from Night Shade books, several of the stories even have Manly Wade Wellman's name make an appearance (Jules de Grandin quoted that he's an expert in the idea of how belief can shape physical reality).
- Showy Invincible Hero: You can guarantee that de Grandin will defeat the villain, but he often does it in a spectacular or cunning fashion and while he's piecing together the mystery, his enemies show themselves to be a terrifying threat to their victims. This keeps the stories from devolving into boredom. Additionally, even when he does defeat the villain, some stories have a Bitter Sweet Ending where he couldn't save the victims afterwards.
- Star-Crossed Lovers: See Tragic Monster below.
- Suddenly Always Knew That: Almost every story de Grandin has this to point of having New Powers as the Plot Demands, one example happens in "Mephistopheles and Company, Ltd." where de Grandin and friends were running from criminals down a beach. Suddenly de Grandin stops and takes off his shoes, he explains that he spent time on the beaches of Japan where there's quicksand everywhere and the locals taught him how to find them. So he leads his companions to safety, but the thugs following them die horribly from the quicksand.
- Summon Bigger Fish: In "The Gods of East and West" a woman has become possessed by the dark goddess Kali, who's manifesting to her through a statue. So Jules brings in a Native American shaman who summons the Great Spirit to battle Kali.
- Sufficiently Analyzed Magic: de Grandin claims he does not believe in the supernatural, rather he believes in the "super physical" with magic and supernatural phenomena capable of being rationalized (for example he believes that many of the gods and demons he encounters are just accumulated good or bad thoughts that have been given fuel from the psychic energy of centuries worth of human religious ceremony).
- Super Doc: Trowbridge is a very competent doctor but de Grandin is on another level completely. He's restored the beauty of a young woman who was badly mutilated and successfully re-attached the head and digestive system of a woman who was temporarily turned into a Penanngalan - thus restoring back to full health once her curse had ended.
- Sword Cane: Jules de Grandin's weapon of choice (his other is a small automatic pistol).
- The Roaring '20s: Seabury Quinn wrote from the heights of the Great Depression, but his de Grandin stories are set shortly after the first World War and many of the people in the stories are wealthy flappers at a jazz club. Later stories (collected in the Black Moon omnibus), take place after World War 2 which de Grandin took part in for three years.
- Third Law of Gender-Bending: Alien Flesh, and how. It even plays Eek, a Mouse!! completely straight, with the narrator thinking of how in his old male life mice didn't bother him.
- Tragic Monster: Quite a lot of stories have women who become monsters through misfortune or trickery (or are Cute Ghost Girls); they fall for a male character, and find that they cannot escape their monstrous state short of death, usually in the form of a Heroic Sacrifice for the sake of their beloved. One particular non-supernatural story "The Serpent Woman" had a young mother who had recently lost her snake-charmer husband and baby, go and kidnap the baby of one of her employers as she had gone temporarily mad from her losses. Since the child was unharmed, even the child's father forgave her on account of her tragedy.
- Tulpa: Many of the gods and spirits that Jules de Grandin fought are coalesced from evil thoughts, thwarted desires and religious devotion which lead to these beings becoming manifest.
- Unusual Euphemism: Jules de Grandin may just outdo Captain Haddock— in his debut story alone ("Terror on the Links") we get "Nom d'un petit porc!"note , "Name of a little blue man!", "Nom d'un petit bonhomme!"note , "Nom d'un fusil!"note , "Par le barb d'un bouc vert!"note , and "Mort d'un rat mort!"note . And it just keeps going from there...
- Villain Teamup: In The Devil's Bride the Soviets fund the Union of the Militant Godless which is an alliance where anarchist atheists have joined forces with Leopard Men cults, Kali-worshipping Thuggees, Satanists and Yezidees in an effort to destroy Christianity and other mainstream religions.
- Voodoo Zombie: "The Corpse-Master", an ex-Air Force member had lived in Haiti and learnt to create zombies to serve him. Including do stripteases and kill inconvenient people. Salt would lead to their downfall.
- The Watson: Dr. Trowbridge. Interestingly, his debut (in "The Stone Idol") predates de Grandin's by six years, but he settled into this niche comfortably for the rest of Quinn's career.
- What the Hell, Hero?: Trowbridge is taken aback when Grandin threatens to stab a rather foolish spiritualist in "The Wolf of Saint Bonnot". True, she's kind of a Jerkass and the one responsible for the mess (and almost responsible for preventing the monster from being destroyed)— but she is not deliberately malicious and de Grandin comes off unusually nasty for once.
- Would Hurt a Child: In "The Corpse-Master", including a fairly graphic description of the poor little girl's corpse—leading to Manly Tears and one of Jules de Grandin's fiercest Badass Boasts:"Sang du Sant Pierre, I, Jules Grandin, do swear that I shall find the one who caused this thing to be, and when I find him, though he take refuge beneath the very throne of God, I'll drag him forth and cast him screaming into hell. God do so to me, and more also, if I do not!"
