Schwartz, David, and Marissa Moss.G Is for Googol: A Math Alphabet Book. Tricycle, 1998. Uses the alphabet to introduce mathematical terms, from abacus to zillion. For younger readers.
Crump, Thomas.The Anthropology of Numbers. Cambridge University Press, 1992. Explains the part numbers play across cultures.
Enzensberger, Hans Magnus.Trans. Michael Henry Heim.The Number Devil: A Mathematical Adventure. Metropolitan, 1998. Through a series of dreams, a young boy who hates math explores the amazing world of numbers, including infinite, prime, and Fibonacci numbers. For younger readers.
Maor, Eli.e: The Story of a Number. Princeton University Press, 1994, 1998. A mathematician discusses the history of a number important in theoretical mathematics; intended for the general reader.