A classic that deserves to be read by children and adults alike. I liked this book when I was a child, but of course a lot of Swift's humor went over my head at the time. If you've only ever seen the TV and movie versions with Gulliver stomping around in the land of the Lilliputians, you should read the full volume, in which Gulliver also travels to Brobdingnab, the flying island of Laputa, the academy of Lagado, and the land of the Yahoos and the Houyhnhnms.
In part one, Gulliver visits Lilliput, a land of six-inch tall people ruled by a byzantine court governed by silly and elaborate rituals. On his next voyage (unlike the movie version, he goes home each time), he visits Brobdingnab, where he is the Lilliputian and the Brobdingnabians treat him like a performing pet. Here, he finds a court vastly superior to that of Europe. Then he visits Laputa, Balnibarbi, Luggnagg, and Glubbdubrib, lands with fantastic science (including a Flying Island) and magic (necromancers who can summon ghosts, tragic immortals who age but never die) which they use to absurd purposes. Finally, he visits Houyhnhnmland, ruled by intelligent horses, where humans (Yahoos) are vicious, degenerate animals. The metaphor becomes heavy-handed here, as Gulliver grows to despise himself, wishes to become a Houyhnhnm, and when he's forced to return to England, he can only see his fellow human beings as disgusting, smelly Yahoos.
Each place is funny and fantastic and would make fine bed-time reading for a child, but Swift is always wielding his knife. Sometimes the humor is as subtle as an axe, such as his frequent jibes about princes, ministers, and lawyers, and in the end, Gulliver becomes a bitter misanthrope, but there are also more clever jokes about religion, education, and human vice in general, and even sex. When the Emperor of Lilliput sentences Gulliver to have his eyes put out (fully expecting him to literally lie down and submit to this), adults will see what Swift is saying about the ingratitude of princes and ministers (while Swift's original readers probably saw real-life leaders being caricaturized), while kids will just be laughing at the fact that Gulliver put out a palace fire by pissing on it.
Lastly, since Swift was a satirist with a social consciousness, Gulliver's narrative ends with a commentary (still delivered with sharp, earnest satire) on England's penchant for colonization. This was, after all, the same author who wrote A Modest Proposal
is fun. Just as science fiction, it compares favorably with the pulp adventures that followed two centuries later. I found it to be quite an enjoyable read on a surface level, and would recommend it for any young reader's library, but it's also one of those novels that merits a periodic rereading; I suspect I'd have read it quite differently as a teenager (it probably really appeals to those teenagers who think they have it all figured out when it comes to how screwed up and hypocritical the world is), and I definitely read it differently today, able to appreciate the humor, the fantasy, and the satire. Definitely do not rely on any condensed versions or film adaptations to plug this hole in your cultural education -- read the original!