This might be considered the layman's supplement to Dr. Conant's brilliant On Understanding Science published in 1947 (reported on P. 118 of that year's Service). Where the earlier book (based on a series of lectures) might be considered a precisfor a college science course, this one is for the doctor, the lawyer, the Indian chief- and anyone already interested in science or, conversely, convinced he is not interested. The author does an extraordinary job of telling what goes on in the scientist's mind. He goes back to the beginnings of the modern scientific age, to Galileo, Newton, other pioneers; he reconstructs from their published reports the line of thought each followed, step by step. The result is uniquely interesting experience, exciting reading, made more so by concluding chapters that make science today read like a detective story in its impact on industry and medicine, its relationship to the state under democracy and dictatorship.