From a review of the Japanese-language edition: `A beautifully written book...The statement of the problem is very clear-that is, [the author] claims that one aspect of classical and modern number theory can be considered as the number theory of Hopf maps-and then he solves this problem....skillfully and perspectively organized...This book will be ... Read morea good introductory textbook...There has never been a textbook similar to this....I highly recommend this book.' Michio Kuga, Professor, late of State University of New York at Stony Brook Show Less