BOOK ONE - A Voyage to Lilliput
After a brief chronicle of Gulliver's early years (during which he was apprenticed to Master Bates, an example of the sexual punning common to 18th-century literature), Gulliver signs up as a ship's surgeon (a fairly low-prestige job, as surgeon's tasks included cutting hair) and is shipwrecked in Lilliput. At first, he is imprisoned by the Lilliputians, people six inches high. Then he is (kind of) an honored guest (first named Quinbus Flestrin, or 'Man-Mountain'), as his self-important little hosts think they can use his giant size for their own benefit. In particular, they want to use him as a weapon of mass destruction against the enemy nation of Blefuscu. Their current ethics are contrasted with 'Old' Lilliput, in which society operated according to rational, humane values, in order to demonstrate Swift's belief in the 'devolution' of human history.
The conflict between Lilliput and Blefuscu parodies the endless conflicts between England and France. The egg-breaking question refers to the differences in beliefs and practices concerning Communion between Protestants (Lilliput/England) and Catholics (Blefuscu/France). Gulliver does save Lilliput from a Blefuscudian invasion, after which he receives the honorary title of Nardac.
Gulliver falls out of favor, however, because: he literally eats up their natural resources; he puts out a fire in the Royal Palace by urinating on it, thus offending the Lilliputian Queen and breaking the law; he is accused of having an affair with the wife of Flimnap, the royal treasurer (which would have been a difficult feat, considering the size difference); and he refuses to destroy Blefuscu completely. Flimnap and another royal counselor, Skyresh Bolgolam, draw up official articles of treason against Gulliver. The Lilliputian King denies Gulliver a trial and sentences him to death through blinding and starvation. Gulliver flees to Blefuscu, from whence he ultimately returns to England, taking a few miniature animals with him
BOOK TWO - A Voyage to Brobdingnag
Maritime misadventures land Gulliver in Brobdingnag, a country in which the people are twelve times Gulliver's size. Whereas he had been a giant in Lilliput, he is a midget in Brobdingnag. The size reversals signal moral and ethical reversals; in the main, Brobdingnagians are ethical, practical people as opposed to the egoistic and vicious Lilliputians. Nonetheless, Gulliver encounters a great many difficulties in Brobdingnag.
First of all, he is menaced by his environment: insects, birds, rats, dogs, frogs, and monkeys are deadly dangers to him. Second, he is threatened (emotionally as well as physically) by the very means taken to protect him: considered to be a sort of side-show exhibit, Gulliver is carried about in a cage and his fame takes him to the Royal Palace, where he becomes a freak-pet (rousing the homicidal anger of the King's dwarf, who imprisons him in a marrow bone). Gulliver's custodian during these adventures is a twelve-year-old farmer's daughter named Glumdalclitch (who calls Gulliver Grildrig, which means 'mannikin' or 'doll'), about whom Gulliver has only kind things to say. Her purity is contrasted with other Brobdingnagian ladies at court, who use Gulliver as a sexual toy; his microscopic view of their skin and his amplified perception of their body odors make them revolting to him.
Despite Glumdalclitch's care, Gulliver (in his cage) is abducted by an eagle. The eagle drops Gulliver's cage in the ocean, where it is picked up by a ship; eventually, Gulliver returns to England. He brings with him a small collection of curiosities from Brobdingnag, such as a comb made out of the stubble from the King's beard, and a corn from the foot of a maid-of-honor, which Gulliver plans to have set in silver for a drinking cup.
BOOK THREE - A Voyage to Laputa, Balnibarbi, Glubbdubdrib, Luggnagg, and Japan
As the title suggests, Book Three is somewhat of a hodgepodge. In it, Swift satirizes science, philosophy, history, and theology (!!). In brief, Laputa is a flying island manned by scientist-philosophers totally absorbed in impractical, abstract theories; thus their wives are infamous for their sexual unfaithfulness. The flying island tyrannizes the stationary nation of Balnibarbi; Gulliver's visit there contrasts the practical lifestyle of Lord Munodi with the crazy schemes carried on at the Grand Academy (such as making water run uphill and breeding hairless sheep). These parts of Book Three satirize the vogue for speculative science (and England's Royal Academy), but they also criticize England's colonial tyranny over Ireland.
In Glubbdubdrib, a nation of sorcerers, Gulliver is able to talk to the spirits of the dead; he finds that history is not what he had thought. In Luggnagg he encounters the Struldbruggs, a race of immortals who - unfortunately for them - age eternally without dying. Gulliver's previous wishes for eternal life are exploded by meeting these miserable, senile, decrepit, despised human beings; here Swift may be attacking theological notions of bodily as opposed to spiritual immortality. Finally, Gulliver travels to Japan (the only 'real' destination in Gulliver's Travels, and a country then closed to all foreigners), where he gets into trouble by refusing to trample on a crucifix (a test that the Japanese actually imposed on suspected Europeans at that time). Gulliver is able to catch a Europe-bound ship and return to England.