In these intimate studies of the effect of power upon fifteen United States presidents, from Jefferson to Truman, Mr. Hadley has gambled with an original and imaginative presentation of history and won. While he may have crossed the line separating over-simplification from misrepresentation more than once, he has risked quoting out of context to stimulating effect. His method has seldom been employed, and with the exception of ""In White 'America,"" it has never been employed so well. What he has done is to sift through the tremendous amounts of primary material on each of his chosen subjects, selecting the telling phrases, and then without regard for such niceties as chronology, assembled them in a lively dialogue where the essentials of each situation stand out bold and clear. The results can scarcely please the scholarly, but the dramatic advantages are undeniable. It has a considerable readability (as did his The Nation's Safety and Arms Control- Viking-1961) and the inclusion of the word unique in the title is Justified.