BOOK REVIEWS of t,eehniques and many useful tables and graphs. Part XI. BetsiRays, by Martin Deutsohand Otto Ibfood-Hansen (213pp.) This is alaraesubject, uarticularly if a non. cursory discussion the man> experimental approaches and associated instrumentation is included. The authors have achieved laudable results in presenting the subject in great depth yet retaining conciseness. Theoretical di~cussion i8 a180 excdlent and includes the recent fundamental discovery of non-conservation of parity in the beta-decay process. Part XII. Particle Aeeclerators, by Edwin M. McMillsn (147 pp.). This srthjeet helongs in any work titled "Experimontal Kuclear Physics," hut is not closely sssoeintcd with the other four parts of this particular volume. The develop-
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