From the reviews: ..".a fine book ...] When it appeared in 1949 it was a pioneer. Now there are plenty of competing accounts. But Hasse has something extra to offer. ...] Hasse proved that miracles do happen in his five beautiful papers on quadratic forms of 1923-1924. ...]It is trite but true: Every number-theorist should have this book on his or her shelf." --Irving Kaplansky in Bulletin of the American Mathematical Society, 1981