Fifty years ago, a small sparse book came out under the pretentious title Laws of Form. Its author might have once fallen in with the logical philosophers of Cambridge, including Russell and Wittgenstein. But only later, while designing primitive switching circuits for British Rail, did George Spencer Brown come upon the arithmetic underlying Boolean algebra. Laws of Form flips the reduction of mathematics to logic, revealing simple laws of being and knowing that only reflect what great mystics, East and West, have been saying all along. Enthusiastic Mathematics offers the first thorough, philosophical introduction to Laws of Form. With no presumption for logic or mathematics, the reader is delivered into its philosophical vision via a colourful journey through the history of science.