The story tells about the adventures of a straight-forward and practical doctor and ship’s captain. Lemuel Gulliver returns home after three and a half years at sea. He marries and sets up his practice. Since he cannot sustain himself from practicing medicine he returns to sea. He again comes home and sets up another medical practice, which also fails. He contemplates over-charging patients to maintain himself and his wife but he is an honest man and decides to return to sea. This time he leaves Bristol, England on May 4, 1699 aboard the Antelope and sails toward the South Seas.
While heading into the East Indies the ship encounters a storm. The ship sinks and Gulliver is the only survivor. He swims to a nearby island and falls asleep as soon as he reaches the shore. While he is sleeping he is bound by the inhabitants of the island: creatures no more than six inches tall. He wakes up to find his situation. At first they attack him with tiny arrows which are little more than pin pricks to Gulliver. The inhabitants eventually give him food and take him to their emperor.
He discovers he is on the island of Lilliput. The emperor is amazed and entertained by Gulliver and Gulliver is equally entertained by being so lavished by royalty. The emperor soon realizes the Gulliver, with his massive size, could be a resource for the Lilliputians.
Gulliver is enlisted into a war being wages between Lilltput and their enemies from Blefuscu. The war has been raging over a disagreement concerning how to properly crack and egg. In return for helping the Lilliputians defeat Blefescu, the emperor promises Gulliver full access to food and promises the entire staff of tailors to make him new clothes.
Blefescu mobilize 50 ships in order to invade Lilliput. Gulliver simply wades across the sea and breaks the entire navy of Blefescu, forcing them to surrender. In a well-intentioned attempt to help out further, Gulliver extinguishes a fire with his urine.
As much as he becomes a hero to the emperor, he is also a villain to the jealous and scheming admiral of the Lilliputian navy, Skyresh, who schemes against Gulliver. Skyresh manages to have Gulliver charged with treason after which he is sentenced to be blinded. Rather than destroy the Lilliputians, Gulliver decides to escape. He manages to escape to Blefescu where he repairs a boat and sets sail for England.
After being home in England with his wife for two months, Gulliver sets out again on another adventure. This time he reaches the land of the Giants, Brobdingnag. A worker in field discovers him. At first, the farmer thinks little of Gulliver and treats as something of a pet. Eventually, the farmer sells Gulliver to the Queen.
The queen is entertained by Gulliver and his musical talents. Gulliver in turn finds his place and privilege in the royal court fairly easy but he does not particularly like it. He finds the Brobdingnagians to be disgusting due to the fact that their enormous size amplifies all of their bodily functions. When allowed to dance on the naked bodies of the women, he finds their enormous pores to be repulsive and the sound of their torrential urinating is disgusting to him.
Everything about life with the Brobdingnagians is repulsive to Gulliver. Even his life becomes endangered by the enormous animals. The insects leave disgusting slime on food and he is unable to eat. What is more, he finds the Brobdingnagians to be ignorant. So much so that even the king is ignorant of politics. Eventually, on a trip to the country with the royals, his cage is picked up by an eagle and dropped into the sea. He is rescues by an English ship and returns again to England.
After ten days at home, Gulliver is again invited to sea by the captain of the Gladwell. On this voyage Gulliver finds himself in command of a sloop which encounters a storm. They are captured by pirates. With the help of one of the pirates Gulliver is allowed to paddle off in a canoe.
While wandering at sea, Gulliver encounters an island floating in the air. The inhabitants lower a chain and draw him up. The people of this island are described as looking very strange:
Their heads were all reclined, either to the right, or the left; one of their eyes turned inward, and the other directly up to the zenith. Their outward garments were adorned with the figures of suns, moons, and stars; interwoven with those of fiddles, flutes, harps, trumpets, guitars, harpsichords, and many other instruments of music, unknown to us in Europe.
He is escorted to the palace of the king located at the top of the island. The king addresses him in a language Gulliver does not know.
Gulliver discovers that the inhabitants are all scholars who study nothing but theoretical mathematics and music. Their language is based on these two disciplines and they know of nothing else. As a result, their homes, politics, and government are a mess. The people live in fear of their world being destroyed by the sun.
After a time, Gulliver asks to leave the island. He is eventually lowered onto the island of Balnibari. He enters the main city, Lagado, where he finds that the agriculture is in disarray, the people are dressed in ragged clothes, and all of the houses are in disrepair. Gulliver finds that the people of Balbinari learned some of the mathematics from the floating island. They attempted to recreate this system of learning and now have academies in every town.
Since the people of Balbinari learned only a little, everything is mistaken and wrong. They are attempting to extract sunbeams from cucumbers and turn feces into food. They have lost their ability to do anything practical or useful.
Gulliver takes a short trip to nearby islands. He visits Glubbdubdrib and Luggnagg. On Glubbdubdrib he finds magicians who are able to conjure famous historical figures. He meets and speaks with Alexander the Great, Julius Caesar, and Brutus. The magicians conjure the entire Roman Senate.
When he visits Luggnagg, Gulliver meets Strulbrugs: people who live forever. Some live on in eternal youth, while others grow old and infirm. Eventually Gulliver finds his way all the way to Japan where he encounters a Dutch ship which takes him home again to England.
On Gulliver’s fourth journey he sets sail as a ship’s captain on the merchant ship The Adventurer. After several months sailing to the South Seas the men on board mutiny and set Gulliver adrift on a longboat. He drifts to a land inhabited by the Houyhnhmns, creatures which are intelligent horses.
The island is also inhabited by Yahoos, creatures with human faces but which walk on all fours and are partially covered with hair.
Gulliver is soon surrounded by Yahoos. Some of the Yahoos climb a nearby tree and begin defecating on him but he is rescued by two Houyhnhmns. They take Gullvier back to their house where Gulliver sees cows working as domestic servants. Behind the house there are several Yahoos tied by their necks who are feeding on dead dogs and other animals.
Gulliver eventually learns the language and customs of the Houyhnhmns. He admires the gentle nature and civilized ways of the Houyhnhmns, but over time they become suspicious of him. They fear he will blend in with the Yahoos and lead them to rebellion. He builds a canoe and makes a sail from Yahoo skins and sails to a nearby rocky island. He is eventually rescued by a Portugese ship, which takes him all the way to Lisbon. Gulliver then makes his way back to England for the last time.
