Lemuel Gulliver is a married surgeon from Nottinghamshire, England, who has a taste for traveling. He heads out on a fateful voyage to the South Seas when he gets caught in a storm and washed up on an island. This island, Lilliput, has a population of tiny people about 6 inches tall. They capture Gulliver as he sleeps and carry him to their capital city, where they keep him chained inside a large abandoned temple outside the city walls.
Gulliver becomes a great friend of the Emperor of Lilliput, who introduces Gulliver to many of their customs. For example, instead of staffing his cabinet with capable administrators, the Emperor chooses guys who perform best at a dangerous kind of rope dancing. The Emperor asks Gulliver to help him in his war against Blefuscu, a similarly tiny kingdom across a channel of water. Gulliver agrees and uses his huge size to capture all of Blefuscu's navy.
In spite of the great service that Gulliver has done for the Lilliputians, he has two terrible enemies, who seem to be jealous of his strength and favor with the Emperor: the admiral Skyresh Bolgolam and the treasurer Flimnap. These two men conspire to influence the Emperor to have Gulliver executed. They serve Gulliver with a series of Articles of Impeachment, with the final sentence that Gulliver is going to be blinded. (The ministers also decide, in secret, that they are going to starve Gulliver to save money on the enormous amount of food he eats.) Gulliver is informed of this plot against him by a friend at the Lilliputian court. He manages to escape to the island of Blefuscu. Fortunately for him, a human-sized boat washes ashore on Blefuscu. Gulliver rows to nearby Australia and finds a boat to take him back to England.
Gulliver heads out to sea again after a brief stay in England with his family (who, we have to say, he doesn't seem to like all that much). Once again, a storm blows up, and Gulliver winds up on the island of Brobdingnag. The Brobdingnag are giants 60 feet tall, who treat Gulliver like an attraction at a fair. Gulliver comes to the attention of the Brobdingnagian Queen, who keeps him like a kind of pet. She is amused, because he is so tiny and yet still manages to speak and act like a real person. This Queen employs a young girl, Glumdalclitch, to look after Gulliver and teach him their language. Glumdalclitch does this with great affection.
While Gulliver lives at the palace, he is constantly in danger: bees the size of pigeons almost stab him, a puppy almost tramples him to death, a monkey mistakes him for a baby monkey and tries to stuff him full of food. Because Gulliver feels ridiculous all the time, he starts to lose some of the pride and self-importance he couldn't help having in Lilliput.
The Brobdingnagian King reinforces this new sense of humility. After Gulliver describes to him all that he can think of about English culture and history, the King of Brobdingnag decides that the English sound like tiny little pests. He absolutely refuses to accept Gulliver's gift of gunpowder because such weapons seem like an invitation to horrible violence and abuse.
Finally, Gulliver leaves Brobdingnag by a bizarre accident and returns home to England. He only stays there for about two months, however, when he goes to sea again. This time, he gets marooned by pirates on a small island near Vietnam. As he's sitting on this island, he sees a shadow passing overhead: a floating island called Laputa. He signals the Laputians for help and is brought up by rope.
The Laputians are dedicated to only two things, mathematics and music. But their love of equations makes them really poor at practical things, so no one in the kingdom can make a good suit of clothes or build a house. And in imitation of the Laputians' abstract science, the residents of the continent below, Balnibarbi, have been steadily ruining their farms and buildings with newfangled "reforms."
Gulliver also visits Glubbdubdrib, an island of sorcerers where he gets to meet the ghosts of famous historical figures, and Luggnagg, an island with an absolute king and also some very unfortunate immortals. He makes his way to Japan and then back to England once more – this time, for five months, before he sets out again, leaving his family behind once again.
This time, Gulliver sails out as a captain in his own right, but his sailors quickly mutiny against him and maroon him on a distant island. This island is home to two kinds of creatures: (a) the beastly Yahoos, violent, lying, disgusting animals; and (b) the Houyhnhnms, who look like horses. The Houyhnhnms govern themselves with absolute reason. They do not even have words for human problems like disease, deception, or war. As for the Yahoos – they are human beings. They are just like Gulliver, except that Gulliver has learned to clip his nails, shave his face, and wear clothes.
In Houyhnhnm Land, Gulliver finally realizes the true depths of human awfulness. He grows so used to the Houyhnhnm way of life that, when the Houyhnhnms finally tell him he must leave, he immediately faints. Gulliver obediently leaves the land of the Houyhnhnms, where he has been very happy, but he is so disgusted with human company that he nearly jumps off the Portuguese ship carrying home.
Once Gulliver returns to his family, he feels physical revulsion at the thought that he had sex with a Yahoo female (his wife) and had three Yahoo children. He can barely be in the same room with them. We leave Gulliver slowly reconciling himself to being among humans again, but he is still really, really sad not to be with the Houyhnhnms. In fact, he spends at least four hours a day talking to his two stallions in their stable. Lesson learned from Gulliver's Travels: the more we see of humans, the less we want to be one.