As the title might suggest the story focuses on Han Solo, specifically on his adventures in the years leading up to A New Hope as he goes from Street Urchin and petty thief to Imperial pilot to the Loveable Rogue we all know and love.Confusingly this trilogy is the second trilogy of books to focus on Han Solo's early life. Nearly twenty years earlier Brian Daley had written The Han Solo Adventures, three stand alone stories about Han's escapades as a smuggler. Crispin retroactively fitted Daley's books into her series so that they now canonically take place during Rebel Dawn. So the chronology goes:The Paradise Snare -> The Hutt Gambit -> The beginning of Rebel Dawn -> The Han Solo Adventures -> The rest of Rebel Dawn.
Affably Evil: Crispin does the impossible and makes Jabba somewhat likable. Jabba seems to have a genuine soft spot for Han, he's better than most of his fellow Hutts at least, and they consider him deranged due to his fetish for humanoid females.
Anti-Hero: Han is mostly a Type II, Bria starts as a Type I and ends up a Type IV.
Been There, Shaped History: Bria was part of the Rebel unit that stole the plans for the first Death Star, before transmitting them to Princess Leia's ship. The unit then committed suicide to prevent imminent capture and interrogation by the Empire.
Bizarre Alien Biology: Hutts, like slugs, (their closest real-world equivalent, which is also used as an insult for them) are hermaphrodites , with both male and female sex organs. After reproducing they identify as female, but apparently can go back to identifying as male later (as Durga and Jabba's parents do).
Black and Gray Morality: The Rebels aren't nearly the paragon of virtue they are in the films, but several key members who canonically steer it in a more honorable direction haven't joined the movement yet, and they haven't even become the Rebel Alliance until the last book, with the unification of three major groups, so there's lots of different ones, and no one to give a What the Hell, Hero? speech if any of them go too far. In particular, the Corellian Resistance's Red Hand Squadron only gives no quarter to slavers, so it's more sympathetic than it might otherwise be.
Bolivian Army Ending: Bria Tharen and her Red Hand Squadron. Boba Fett later confirms her death when he brings news of it to Han.
Cat Folk: The Togorians. As a nod to Real Life lions (although they actually come in all the colors and fur patterns of felines), the males are aggressive warriors while the females are intelligent, political plotters, and adept at mechanical and scientific endeavors. They also live separately most of the time, with males still hunting for food, and have different governments.
Emperor Palpatine (as usual) who instigates the Imperial attack on the home system of the Hutts as well as its failure all in order to disgrace an Imperial Moff that was getting too big for his britches.
Xizor, even more so: he exploits the ongoing war between the Desilijic and Besadii Hutt clans in order to basically perform a takeover of Besadii, granting him a priceless foothold in the Outer Rim.
Early-Bird Cameo: In a sense. This trilogy marks the first appearance of Baron Soontir Fel - Crispin asked Michael Stackpole about whether there were any good Imperial pilots available, and Stackpole came up with Fel, later featuring him in the X-Wing Series.
Deface of the Moon: Mako, a friend of Han's from the Academy tried to deface the Imperial insignia on the nearby artificial moon, but underestimated the power of the antimatter used and ended up destroying said moon.
Doomed by Canon: It is pretty obvious that Han and Bria are not going to end up together...
Earth-Shattering Kaboom/Orbital Bombardment: The Imperial Moff running the sector orders a Base Delta Zero (total destruction operation) against Nar Shaddaa in The Hutt Gambit. The Hutts buy off the admiral in charge, who is separately ordered by Coruscant to withdraw at his earliest convenience to make the Moff look bad. Vader Force-chokes the admiral to death, ostensibly for accepting the bribe, to cover up the shady goings-on.
Has a Type: Han with anti-Imperial revolutionaries. His first love Bria becomes one by the end of the trilogy, while another lover,Xaverri, is already one when he meets her, and, of course, Leia in the movies and later expanded universe.
Heartbroken Badass: Han, after Bria leaves him at the end of the first book, oh so very much. Plays a big part in forming the cynical personality he's developed by the time we meet him in the movies.
Insignia Rip-Off Ritual: Han went through this after he was court-martialed and cashiered for preventing a superior officer from killing Chewbacca when he was a rebellious slave (which also lets Chewie escape). When he dreams about it later, it ends with him attacking the officer who did it.
Mad Oracle: Han, Chewie, and Mako encounter one during The Hutt Gambit, who claims that Han will face betrayal from those he trusts (Bria in Rebel Dawn, Lando in The Empire Strikes Back, Mako in Dark Empire, Zeen, Kid DXo'ln, Wynni and Ana Blue in The New Rebellion, and finally his own son in Legacy of the Force. She doesn't mention anybody by name, but stares at Mako, who's with him), will be rich but only after he no longer cares about it, will be a great warrior, and will do much for love. Han, of course, is skeptical (not to mention drunk), and has forgotten about it by the next day.
Mama Bear: Dewlanna's response to Shrike attempting to beat Han to a bloody pulp is a good example of why you should never piss off a Wookiee.
During Han's painful memory of his Insignia Rip-Off Ritual he makes mention of his Corellian Bloodstripe (the red and yellow stripes that he wears down the seam of his pants). It's an honor given out by the government of Corellia so it's the only one he gets to keep, but we're never told just what he did to earn it. Even in later novels we're never told what happened except that it was a very harrowing and painful experience that happened over several days. Furthermore there are two classes (Red for First Class and Yellow for Second Class) of Bloodstripes and he's earned them both.
Notably the Noodle Incident mentioned in The Empire Strikes Back happens in Rebel Dawn (where Lando appears furious at Han when they meet again over "that stunt you pulled"). The Corellian Resistance screws Han and his smuggler pals out of their share of the treasure owed to them in the raid on Ylesia, even turning their guns on them, because they need it to fund their search for the Death Star plans, along with the rebellion in general. To Lando and the others, it looks like Han was complicit in the betrayal rather than also being a victim of it himself, because Han was the one who brought them the Corellian Rebels' proposal in the first place.
Parental Substitute: Dewlanna, who watched over Han on the Trader's Luck, and sacrificed her life to help him escape.
Path of Inspiration: The Cult of The One and The All, created by the Besadii Hutt clan and run by the T'landa Til, who use their mating call to ensnare "pilgrims" for slave labor.
Psychic Strangle: Darth Vader executes Adm. Winstel Greelanx for accepting the Hutts' bribe.
Running Gag: Anytime Kibbick the Hutt is mentioned it is pointed out that he is an idiot.
Slavery Is A Special Kind Of Evil: a view shared by the protagonists throughout the series. Han runs away from his first job as a pilot for the Besadii Hutts when he discovers that their main business is slavery (freeing a slave he'd fallen in love with in the process); later resigns in disgrace from the Imperial Starfleet after freeing another slave from his brutal Imperial taskmaster Chewbacca, who escapes to pledge Han a life debt for it; and specifically only accepts a job smuggling for Jabba after he's made it clear that he will never transport slaves for him. Bria and Chewbacca, being former slaves themselves, naturally share this outlook which is a big part of the reason Bria joins the Rebellion, but contempt for slavery is widespread even beyond that - Lando's way of expressing contempt for bounty hunters, for instance, is that they're "on a level with slavers." Given that the protagonists and their friends are all drug smugglers, con artists, and other "scoundrels," arguably a case of Even Evil Has Standards.
Sound-Only Death: Vader Force-choking Greelanx for taking a bribe and throwing the battle of Nar Shaddaa.
Start of Darkness: Mako Spince is a pretty likable character here. In fact, he's one of the heroes of the story. In the third book, however, he gets captured by Space Pirates, tortured, and crippled for life. When Han and Lando visit him, he refuses to speak to them and makes it clear by his body language that he wants them to leave. When he next encounters Han years later, he sells his old friend out to The Empire. Not because he's under any pressure to do so as Lando was in Empire, but just for credits.