The book begins with a short preamble in whichLemuel Gulliver, in the style of books of the time, gives a brief outline of his life and history before his voyages. He enjoys travelling, although it is that love of travel that is his downfall.

During his first voyage, Gulliver is washed ashore after a shipwreck and finds himself a prisoner of a race of tiny people, less than 6 inches tall, who are inhabitants of the island country ofLilliput. After giving assurances of his good behaviour, he is given a residence in Lilliput and becomes a favourite of the court. From there, the book follows Gulliver's observations on the Court of Lilliput. He is also given the permission to roam around the city on a condition that he must not harm their subjects. Gulliver assists the Lilliputians to subdue their neighbours, the Blefuscudians, by stealing their fleet. However, he refuses to reduce the island nation of Blefuscu to a province of Lilliput, displeasing the King and the court. Gulliver is charged with treason for, among other "crimes", "making water" in the capital (even though he was putting out a fire and saving countless lives). He is convicted and sentenced to be blinded, but with the assistance of a kind friend, he escapes to Blefuscu. Here he spots and retrieves an abandoned boat and sails out to be rescued by a passing ship, which safely takes him back home. This book of theTravelsis a topical political satire.

Part II: A Voyage to Brobdingnag[edit]20 June 1702^[4] 3 June 1706^[5]Gulliver Exhibited to the Brobdingnag Farmer(painting byRichard Redgrave)

When the sailing shipAdventureis blown off course by storms and forced to sail for land in search of fresh water, Gulliver is abandoned by his companions and found by a farmer who is 72 feet (22m) tall (the scale ofBrobdingnagis about 12:1, compared to Lilliput's 1:12, judging from Gulliver estimating a man's step being 10 yards (9.1m)). He brings Gulliver home and his daughter cares for Gulliver. The farmer treats him as a curiosity and exhibits him for money. Since Gulliver is too small to use their huge chairs, beds, knives and forks, the queen commissions a small house to be built for him so that he can be carried around in it; this is referred to as his 'travelling box'. Between small adventures such as fighting giant wasps and being carried to the roof by a monkey, he discusses the state of Europe with the King. The King is not happy with Gulliver's accounts of Europe, especially upon learning of the use of guns and cannons. On a trip to the seaside, his travelling box is seized by a giant eagle which drops Gulliver and his box into the sea, where he is picked up by some sailors, who return him to England.

This book compares the truly moral man to the representative man; the latter is clearly shown to be the lesser of the two. Swift, being in Anglican holy orders, was keen to make such comparisons.

Part III: A Voyage to Laputa, Balnibarbi, Luggnagg, Glubbdubdrib, and Japan[edit]5 August 1706^[6] 16 April 1710^[7]Gulliver discovers Laputa, the flying island (illustration byJ.J. Grandville.)

After Gulliver's ship was attacked by pirates, he ismaroonedclose to a desolate rocky island near India. Fortunately, he is rescued by the flying island ofLaputa, a kingdom devoted to the arts of music and mathematics but unable to use them for practical ends. Since Swift was in Anglican holy orders, he, like so many of them, viewed reason as whatMartin Lutherhad called "that great whore" and regardedDeism, whose practitioners attacked revealed religions, with pure horror.^{[citation needed]}

Laputa's custom of throwing rocks down at rebellious cities on the ground seems the first time that the air strike was conceived as a method of warfare.^{[citation needed]}Gulliver tours Laputa as the guest of a low-ranking courtier and sees the ruin brought about by the blind pursuit of science without practical results, in a satire on bureaucracy and on theRoyal Societyand its experiments. At the Grand Academy of Lagado, great resources and manpower are employed on researching completely preposterous schemes such as extracting sunbeams from cucumbers, softening marble for use in pillows, learning how to mix paint by smell, and uncovering political conspiracies by examining the excrement of suspicious persons (seemuckraking).

Gulliver is then taken to Balnibarbi to await a trader who can take him on to Japan. While waiting for a passage, Gulliver takes a short side-trip to the island ofGlubbdubdrib, where he visits a magician's dwelling and discusses history with the ghosts of historical figures, the most obvious restatement of the "ancients versus moderns" theme in the book. In Luggnagg he encounters thestruldbrugs, unfortunates who are immortal. They do not have the gift of eternal youth, but suffer the infirmities of old age and are considered legally dead at the age of eighty. After reaching Japan, Gulliver asks the Emperor "to excuse my performing the ceremony imposed upon my countrymen oftrampling upon the crucifix," which the Emperor does. Gulliver returns home, determined to stay there for the rest of his days.

Part IV: A Voyage to the Country of the Houyhnhnms[edit]7 September 1710^[8] 5 December 1715^[9]Gulliver in discussion with Houyhnhnms (1856 lllustration byJ.J. Grandville.)

Despite his earlier intention of remaining at home, Gulliver returns to the sea as the captain of a merchantman as he is bored with his employment as a surgeon. On this voyage he is forced to find new additions to his crew, whom he believes to have turned the rest of the crew against him. His crew then mutiny, and after keeping him contained for some time resolve to leave him on the first piece of land they come across and continue as pirates. He is abandoned in a landing boat and comes upon a race of hideous, deformed and savage humanoid creatures to which he conceives a violent antipathy. Shortly afterwards he meets a race of horses who call themselvesHouyhnhnms(which in their language means "the perfection of nature"); they are the rulers, while the deformed creatures calledYahoosare human beings in their base form.

Gulliver becomes a member of a horse's household, and comes to both admire and emulate the Houyhnhnms and their lifestyle, rejecting his fellow humans as merely Yahoos endowed with some semblance of reason which they only use to exacerbate and add to the vices Nature gave them. However, an Assembly of the Houyhnhnms rules that Gulliver, a Yahoo with some semblance of reason, is a danger to their civilisation, and expels him.

He is then rescued, against his will, by a Portuguese ship, and is surprised to see that Captain Pedro de Mendez, a Yahoo, is a wise, courteous and generous person. He returns to his home in England, but he is unable to reconcile himself to living among 'Yahoos' and becomes a recluse, remaining in his house, largely avoiding his family and his wife, and spending several hours a day speaking with the horses in his stables; in effect becoming insane.

This book uses coarse metaphors to describe human depravity, and the Houyhnhms are symbolised as not only perfected nature but also the emotional barrenness which Swift maintained that devotion to reason brought.