

The fundamental unit of the Planiturthian universe is the philosophon, a unit of logic so tiny that only a philosopher could hope to split it.)"

Planiturthian philosophers would like to think that the Planiturthian universe is built from philosophy. Planiturthian biologists would like to think that the Planiturthian universe is built from biology. Planiturthian physicists would like to think that the Planiturthian universe is built from physics. "Is Planiturth's universe built from mathematics? Or is mathematics built by the minds of Planiturthians? Planiturthian mathematicians would like to think that their universe is built from mathematics, but that's only natural, after all. It's filled with illustration to help visualize the concepts, and the stories around which the concepts are introduced are reminiscent of Alice's Adventures in Wonderland (well, the fact that chapters have names like The Topologist's Tea-Party and Along the Looking-Glass probably helps), and this gives the book a whimsical tone (that's a benefit).
