I love this, too. There’s been an animated cartoon made of it, and it “inspired” an episode of the original Outer Limits. There have been a number of sequels and imitators, of which I recommend two:
Sphereland (don’t recall author) takes this to the realm of General Relativity, introducing the idea of the Expansion of the Universe, made somewhat more comprehensible by showing the expansion of the Flatland universe as an expanding sphere.
The Planiverse by A.K. Dewdney, one-time columnisst for Scientific American. Dewdney apparently ran a newsletter about the Planiverse for years (Martin Gardner reported on it in his SA column), and he distilled the best bits into this one story. The Planiverse is a Flatland with an actual working physics, chemistry, and biology. It’s not just geometric characters inhabiting a plane with vaguely defined gravity – Dewdney’s Planiverse creatures live on discs with 2-D gravity and have a well-worked-out biology and anatomy. Some of the conclusions and ramifications are pretty interesting, but it’s all consistent. (How do you fight a war in a Planiverse? At most, two combatants can see each other at a time, so it comes down to a series of individual combats. How can planiversian circulatory and respiratory systems work without cutting the creatures in half? etc.)
Other random weird books:
** Rats, Lice, and History: The Biography of a Disease** – The bio of Typhus, rendered in a weird way. Interesting footnotes. I’m convinced that Diamond stole the form of this title for his own “Guns, Germs, and Steel”.
The Knowledge Web and The Pinball Effect by James Burke – The author/host of Connections and The Day the Universe Changed strikes again. A lot of the stuff in these books showed up in his later Connectionsd series on cable, but these books are written differently from the earlier companion volumes – no color pictures (although some black and white ones), but there are numbers directing you, not to footnotes or end notes, but to other places in the book. It’s sort of the print equivalent of hyperlinks. It makes for a non-linear reading experience.
web of Magic (forgot the author) – a stranfge book, part fiction, part personal memoir, exploring the practice of magic by fakirs abnd magicians in India. The author’s description of his own hardships in making his way to and meeting with practitioners is as strange as the fictional chapters where he describes people learning to use magic.
** Cultural Materialism** by Marvin Harris. Cultural Anthropologist Marvin Harris has written a number of popular books explaining his theory of Cultural Materialism that I find irresistable. He tries to account for the taboo on cows in India, on eating pig among a number of people in Africa and Asia, and for Cargo Cults, among a great many other things. But this is a more technical book explaining and defending his turf, his theory, against all other comers. Deciphering his descriptions is a challenge for an outsider like me (“etic” vs. “emic” distinctions), but it’s worth it to watch him lace into competing theories, like Structuralism. Watching anthropologists duke it out is as much fun as watching theologians battle.