Nearly all the results of modern research are published in short technical articles, of interest only to those who are working in the same or allied fields. Occasionally, some man, well versed in the details of subject, will summarize the work of a given field in a book. If it is well written by one who combines with thorough knowledge of the subject the imagination necessary to view the work in its proper perspective and to give it a setting among more familiar realities, the book is welcomed by all students of physics. Unfortunately, there are not many such books, but when one does appear this department will call attention to the fact.