James Henry Trotter was a young boy who lived a happy life with his parents, until they were eaten by a rhinoceros (yes, really). Afterwards, he is sent to live with his abusive aunts, Spiker and Sponge. One day, James meets a strange old man who gives him a bag of magic "crocodile tongues", which can make James' life better. James accidentally drops the bag on his way home, which causes the contents to sink into the ground. Soon, a nearby peach tree starts to bear fruit, namely, the titular giant peach, which grows to about twice the size of the tree. One night, James crawls into a hole in the peach, and discovers a group of huge, talking insects (another result of the "crocodile tongues"), who befriend James, and they all decide to travel to New York City in the peach (initially by floating the peach on the Atlantic Ocean, then by flying through attaching seagulls to it) to start their lives anew.The book was made into a 1996 live-action/stop-motion animated film from Disney, directed by Henry Selick (who also directed The Nightmare Before Christmas), and with songs written by Randy Newman. Despite doing poorly at the box office, and getting lukewarm reviews upon it's original release, it has since become a Cult Classic, and is one of the better adaptations of Dahl's work, though it can be considered... trippy.
Tropes shared by book and film:
Abusive Parents: James' aunts, Spiker and Sponge (for a given definition of "parent").
Alien Lunch: The foods the bugs sing about in "Eating the Peach"—like curried slugs and plates of soil with engine oil.
Artistic License - Biology: According to his backstory, James Henry Trotter's parents were eaten alive by an escaped zoo rhinoceros. In real life, rhinos are herbivores (they are the largest extant perissodactyls, i.e. related to horses). The film adaptation averted this by changing said rhino from an actual rhinoceros to a large rhinoceros-shaped demon made entirely out of thunderclouds.
Beauty Equals Goodness: Not really. While Aunt Spiker and Aunt Sponge are hideously ugly, with James (and his parents, the short time they appear) being notably easier on the eyes, the bugs are Ugly Cute at best.
Carnivore Confusion: There's a bit of a disconnect with a spider and a centipede being amongst the other invertebrates. This is even lampshaded in the film, with Ms. Spider noting how the peach tastes "better than ladybugs" (with Mrs. Ladybug getting understandibly miffed).
This can be justified since they just recently gained their sentience.
Cassandra Truth: In the book, the flying peach is spotted by the crew of a ship during its flight over the ocean, though only the Captain has binoculars and can see it more clearly. When he starts talking about giant insects, the crew comment that he's "been at the whiskey again" and go fetch the ship's doctor.
In the movie, the New Yorkers initially don't believe James when he tells them about the bugs and about flying across the ocean. Spiker and Sponge try to work this by claiming he's a pathological liar.
Deadpan Snarker: Centipede, in both book and movie, is a loud one. In the movie, Miss Spider is a more subdued and genuinely deadpan one, leading to a few moments of Snark-to-Snark Combat between the two. In the book, the Earthworm has a more sarcastic edge and is the one who engages in Snark-to-Snark Combat with the Centipede.
Early-Bird Cameo: The book contains references to Vermicious Knids, Whangdoodles, Snozzwangers and Hornswogglers, all creatures later mentioned in other Roald Dahl books.
There are a few more ideas in this book that would later be used in the two Charlie books. The peach smashes into and partially destroys a chocolate factory on its wild ride towards the sea (to the delight of many children, who are suddenly swimming in chocolate). The Centipede also sarcastically mentions "skyhooks" as a possibility for hauling the peach out of the ocean, an answer Willy Wonka gives Grandma Josephine in Charlie and the Great Glass Elevator when she asks what's keeping the Great Glass Elevator up.
Make a Wish: How he gets the crocodile tongues (and in a roundabout way, how he uses them)
Miles Gloriosus: Centipede. In the book, he's always going on about what a dangerous pest he is, but he's really pretty harmless. In the movie, he also brags about being a globetrotter, but his knowledge about navigation and geography are severely lacking. Turns out all his knowledge comes from the time when he lived between two pages of an old issue of the National Geographic magazine.
Parental Substitute: The bugs become this for James, particularly Miss Spider and the Grasshopper.
Police Are Useless: Are they ever. When James's aunts are outed for all the abuse they've done to James, they go after him with axes, while the Police and the Fire department play crowd control and leave James to fight off his aunts.
Played with in the book as well, where the policemen and firemen spend most of their on-page time panicking upon seeing the bugs and naming the various kinds of monsters they think they're seeing. There's no actual danger involved here, since the bugs are all friendly.
Rhino Rampage: At the start, both of James' parents are killed by an escaped rhino.
There are a couple of differences in how the bugs end up from book to film. The Grasshopper, Earthworm and Glowworm are the same, but the rest of them are different:
The Centipede, who in the book is borderline obsessed with his many boots, becomes the spokesperson for a high-class firm of boot and shoe manufacturers. In the film, where he only has one pair of boots (because most of his many legs are depicted as arms) he instead runs for Mayor of New York, promising "the Moon and then some" — with no clue provided as to whether he actually won the election or not.
Miss Spider, in the book, teams up with the Silkworm (who doesn't appear in the movie) and learns to produce nylon thread and sets up a factory that makes ropes for tightrope-walkers. In the film, she opens a saucy night club in New York called, appropriately, "Spider Club."
Mrs. Ladybug, in the book, marries the head of the New York City Fire Department thanks to a life-long fear that house was on fire and her children all gone. In the movie, she becomes a highly-respected obstetrician, with her headline declaring: "Dr. Ladybug Delivers 1,000th baby."
Tropes exclusive to the book:
Adults Are Useless: And giant bugs aren't much more useful. Though they have skills and knowledge that can be put to good use, James is the clear leader, he's the one who has all the good ideas, and he's the one everyone turns to in times of crisis.
Ambiguous Gender: The Silkworm is referred to as a "he" by the Old-Green-Grasshopper, but later on as a "she" by the narrative.
Cheerful Child: James, in direct contrast to his more anxious film counterpart.
Do Not Taunt Cthulhu: The Cloud People are pretty sinister from the get-go, but are too astonished at the sight of the flying peach to attack... so of course the Centipede has to call them names and make rude gestures just to show he's not afraid of them. The others immediately call him out on it, but by then the damage is already done and the peach is under attack.
Heavy Sleeper: The Silkworm, who spends most of the book fast asleep.
Acting for Two: In addition to playing Aunt Sponge, Miriam Margoyles also voices the Glowworm.
Adaptation Expansion: In the original book, the only major trouble in the journey is the confrontation with the Cloud People. In the movie, there's a mechanical shark, a trip to the North Pole with undead pirates and facing the Sky Rhinoceros.
Adapted Out: The Silkworm doesn't appear in the movie. Given how she was an extremely minor character in the book who never even got a spoken line of dialogue and what little function she performs in the plot is easily taken over by Miss Spider, the loss is barely noticable.
The Cloud People also don't appear in the movie, having essentially being replaced with the skeleton pirates.
Art Shift: In the movie, James has a Disney Acid Sequence dream about his aunts finding him. The art shifts from stop-motion to cutout animation, kind of like Slow Bob In The Lower Dimension, a short directed by Henry Selick.
More obviously, the style changes significantly after James enters the peach.
Ascended Extra: The Rhinoceros gets this treatment in the film. Being originally just a normal rhinoceros escaped from the zoo, it is here a supernatural beast made of clouds and lightning.
Bag of Holding: Ms. Ladybug pulls out a hand mirror (Which is about half her size), a megaphone, three bouquets of fully bloomed flowers, and Grasshopper's top hat and cane!
Because You Were Nice to Me: When James notes to Ms. Spider how kind she is with him she replies that its because he was kind to her first; she happens to be the spider on the window of James' bedroom, the one which he saved from his aunts.
Beta Couple: Debatable. Most fans of James and the Giant Peach movie end up pairing Mr. Grasshopper and Mrs. Ladybug together for no reason other that they are simply there and single.
Big "NO!": James does this in the movie version when he is falling into the peach while the peach is falling onto the Empire State Building.
Brooklyn Rage: Centipede in the movie. The others even call him "The Yank," and at one point he even shouts "I'm from Brooklyn!"
Canon Foreigner: The Skeleton Pirates did not appear in the book. In the movie, they've replaced the Cloud People, maybe to give the characters some foes to fight away from the peach instead of another case of "defending the peach against attackers."
Character Development: As opposed to the book, most of the main characters go through a small character arc.
James spends much of the movie being timid and scared of his aunts and the rhino, but in the end learns to face his fears and stand up to them.
The Centipede starts out as a JerkassMiles Gloriosus who makes bold claims but is essentially useless when callee upon to actually do something. Over the course of the movie he takes a level in both Kindness and Badass and becomes a hero in the end.
Miss Spider, though affectionate towards James, is aloof and reserved with the other bugs (except with the Cenipede, to whom she's openly hostile), but eventually warms up to them all and becomes friendlier.
The Earthworm, at first, is incapable of seeing the positive side of anything, but while he never quite loses his fundamental pessimism he learns how to "look at it another way."
Mr. Grasshopper starts out as a class-conscious snob, and becomes... less of a class-conscious snob.
Not sure how class-conscious Mr. Grasshopper is—Centipede aside, he seems to interact just fine with the other insects, especially Mrs. Ladybug, who appears to be middle-class at most. It might be more accurate to say he has a serious suspicion of Centipede's claims (which ends up being justified) but comes to appreciate the lengths to which Centipede is willing to go to save them. Based on his honest, obvious dismay at Centipede's "pesticide" and the violin performance on the peach, it almost looks like Mr. Grasshopper goes through the biggest change in terms of one-on-one relationships.
Dark Is Not Evil: Miss Spider. Although she is naturally solitary and mysterious and the other bugs seem to have some fear of her, she is at heart a good-natured and hospitable character, especially to James. He did save her life in the beginning, after all.
Foreshadowing: If you look closely in the first few minutes of The Movie, you can see the various insects and bugs that will have a larger role later on in the film. Even the Empire State Building is seen as a cloud!
Friendship Song: The Film has the song "Family". A song about how the denizens of the peach have come so far together because of James, and that they care for him just like family.
Get Thee to a Nunnery: Modern day viewers will hear Grasshopper's infamous "You, sir, are an ass!" line and think he means "ass" as in "asshole." When the movie was made, "ass" was more commonly used to refer to someone who was particularly stubborn.
Slasher Smile: Mrs. Ladybug and Miss Spider pull one off in the movie, when they both meet James. Subverted in that they were actually smiling normally, but the lighting and James' terror made their smiles look more sinister.
Someone's Touching My Butt: When the lights are out and everyone's fallen on each other, the Centipede tries to pinch Miss Spider but instead pinches the Earthworm. Then the Spider tries to smack the Centipede and ends up hitting the Grasshopper.
Spared by the Adaptation: Spiker and Sponge are squashed flat by the peach early in the book. In the movie they survive and show up for a final confrontation where James gets to stand up to them.
The Stinger: A pretty odd one in the movie. It's a mechanical arcade game called "Spike the Aunts", where figures of the aunts are butted by a rhino.