The most important tool of science is mathematics. This clear and readable book shows even the non-mathematical reader how to use this tool with understanding. Starting with the most basic sort of finger counting, Isaac Asimov proceeds to the pleasures of the abacus, where numbers take physical shapes, and on to the ideas of zero, fractions, and the decimal system. He makes sense of logarithms and even of imaginary numbers, and ends at the very frontiers of mathematics with a discussion of infinity and the concept of an infinity of infinities! The mathematics which Professor Asimov presents is not the thorny wasteland many struggling students suppose it to be. His main concern is not the mathematical techniques one learns in textbooks, but the various wherefores behind them.