Lemuel Gulliver (whose name contains the word gull, or “gull”, but also “foolish, gullible”), is a doctor of a merchant ship, saved from a shipwreck and makes four trips landing in many islands .
In the first Liliput island dwellers are much lower , about six inches. Initially he was captured as a prisoner and then brought to the king. Subsequently Gulliver learn customs and traditions of this new people. Finally, with the consent of the king, he starts for England.
In the second island (called Brobdingnag in Alaska), the inhabitants are giants high twelve times and he had many mishaps from which he saved. Finally a bird raises his room and throws him in the ocean.
In the third island (steering wheel, called Laputa), the inhabitants are scientists, astronomers and philosophers with their heads in the clouds. They are dedicated to experiments abstruse and useless.
The fourth island presents a particular situation. The inhabitants are divided into Houyhnhnms (dominating) and Yahoos (which are submitted). The former are horses who possess reason and have an orderly society, while the latter are a kind of animal that looks like a man, and appear brutal, ignorant, dirty and greedy.
All adventures, in one way or another, represent the ideology pessimistic and negative for Swift, according to which man is selfish, corrupt, ignorant and power-hungry, with only vices and no virtue.