628 ROOK REVIEWS

E. F. TAYLOR and J. A. WHEELER, Spacetime physics (W. H. F r eeman and C o m p a n y Ltd., London , 1966. 208 p., 36s)

Here is a remarkable exper iment in m o d e r n didactics. One envies the " f r e s h m a n " who gets rela- tivity served in such appetizing form. All the resources of the geometrical Minkowski representa t ion are exploited to make the kinematical effects entirely clear, and the pa ins tak ing explanat ions in the text (making full use o f simple mathemat ics ) omit no detail o f the a rgument . The pitfalls and subtle poin ts receive especially careful t rea tment , and here the reader is invited to find the answers to some searching quest ions allowing h im to test his grasp o f the subject. One o f the mos t at tractive features is the precise and detailed discussion, no t only o f fundamen ta l exper iments directly related to the principles, but o f actual applicat ions o f the theory to a variety o f p rob lems of atomic, nuclear and high energy physics; everywhere the actual da ta are presented and analysed, and references to the original papers given. The book is lavishly produced; a varied typography serves to enhance the clarity o f the exposit ion, and the d iagrams m a k e clever use o f grey background to br ing out impor tan t details o f surfaces and volumes left in white. A perusal o f this book will ma tu re the f r e shmen and refresh the ma tu re ones.

L.R.

C. S. W u and S. A. MOSZKOWSKI, Beta decay (Interscience Publishers, New York, 1966. xiv-394 p ~6)

Two substant ia l treatises on fl-decay and weak interactions, by Konop insk i and by Schopper, have jus t appeared; they both cover the g round mos t competent ly and very fully, and should satisfy every- body ' s needs, i na smuch as the former puts more emphas is on the theory, the latter on the experiment . Yet this will no t d iminish our curiosity o f hear ing what Mrs. W u has to say; and indeed, the book she has writ ten with the col laborat ion of such an eminent theoretical expert as Professor Moszkowski does not d isappoint our expectat ions; it has a unique flavour, tha t justifies its existence along with any n u m b e r o f ponderous textbooks. The historical and descriptive chapters, which are the best, are written with such gusto tha t the reader feels h imse l f carried away to a truly fascinat ing adventure. He is also asked, of course, to absorb the prescribed dose o f the usua l C lebsch-Gordan medicine (why misspell poor Gordan ' s name?), but this is done gently enough. Indeed, the book will chiefly assert i tself as an e lementary and inspiring in t roduct ion to the subject. This is no t to say tha t it is wi thout its faults. The theoretical considerat ions are certainly competent , bu t - in contrast to the physical discussions - they are not deep and may even (historically at least) be slightly misleading: thus, the appendix on the theory of the pos i ton ignores the fact tha t the concept ion o f the positive electron mov ing backward in t ime, whose in t roduct ion is ascribed to Feynman , was familiar to theo- reticians ever since the appearance o f Dirac 's first paper on the electron spin, and tha t Heisenberg very soon removed, by slight formal al terat ions, the awkward features o f Dirac ' s original theory. The mos t puzzl ing quest ion about the book, however, is why Mrs. W u chooses to write mev jus t when everybody else has at long last agreed to MeV. As it is highly improbable tha t she should have been seized by the spirit o f the Cul tural Revolut ion, I p resume tha t it is just a pass ing caprice, which it would be in bad taste for anybody to imitate.

L.R.

G. DEARNALEY and D. C. NORTHROP, Semiconductor counters for nuclear radiations, (E. and F. N. Spon Limited, London , 1966. xx-459 p., 80 s.)

In this second edition o f Dearnaley and Nor t h rop ' s valuable m o n o g r a p h (see Nuclear Physics 50 (1964) 693) the s ta tus o f semiconductor counters is competent ly reviewed up to September 1965. Natura l ly , the l i th ium drifted g e r m a n i u m detector is here treated in greater detail t han in the first edit ion whereas the section on homogeneous counters is reduced. Also the o ther sections o f the book are thoroughly revised in view of the new developments , and the 40 page bibl iography is kept up-to- date to 1965. I f the present rapid development in the field o f semiconductor counters is going to continue, a third edit ion is probably needed in a couple o f years.

O. N a t h a n