With Arthur Bryant's The Turn of the Tide (see report P. 318) as June Book of the Month, and this book the mid-summer selection, the American reading public is having a double exposure on the early period of the Second World War in England. This traces in thorough fashion the projected invasion of England in 1940- the German preparations and the British countermeasures. Militarily angled the book seems not destined for a general market, but once past the opening chapters, with minute examination of the directives involved, the plans on both sides the Channel explored, Fleming proceeds to give an immensely interesting impression of the attitude of mind of the British public during those crucial months. Further, he explores the German attitudes, Hitler's strange ambivalence- a ""mirage"" as Fleming terms it, and his retreat from definite participation in preparation for what might well have changed the course of history. Exceedingly significant, too, is the study of the processes of wishful thinking, the expansion of hearsay into fact, the rumors and spy aca the seizing of scraps of evidence to indicate false conclusions -- this both in England and Germany. The final chapters attempts some conjectures as to what might have happened had the plans, far reaching as they were, been brought to completion, if invasion had been effected, if the erratic preparations for occupation been completed. As it stands, Operation Sea Lion brought England- in preparation- to her highest peak of concentrated determination to hold on to victory.