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

Geometrical optics is no longer fashionable. Research workers do not expect significant new discoveries to be made in this field of classical physics. Teachers avoid the subject because its use for many generations in arid mathematical exercises has robbed it of all freshness and stimulus, with the result that it no longer seems relevant to a modern physics course. There remains - and perhaps this has grown in recent year- the technical significance of geometrical optics. It provides the basis for the design of optical instruments for use in everyday life as well as for scientific and...