By far the most poetic math book I've read is Kato/Kurokawa/Saito *Number Theory 1: Fermat's Dream.*
Here's a quote:
"In the long history of mathematics, a number meant a real number, and it is only relatively recently that we realized that there is a world of p-adic numbers. It is as if those who had seen the sky only during the day are marvelling at the night sky. The mathematical scenery is competely different. Q_p emits „the light of prime number p“ in the night sky as if it were a star that we could not see because of the sun, or the real number field R, which emits „the light of real numbers“ during the day. Just as there are countless stars in the night sky, there is one Q_p for each p. What each star is to the sun is what each Q_p is to R. Just as we can see space objects better at night, we began to see the profound mathematical universe through the p-adic numbers."
