Alden Hatch, one of America's most versatile (The Mountbattens, A Man Named John, etc.) and popular biographers, has written what is undoubtedly the important study of Pope Paul VI to appear to date. Not so much a biography in the usual sense of the word as a study of the subject's characteristics, accomplishments, and orientation, Pope Paul VI, nonetheless, manages to capture the drama and color of world events in which Paul has been involved, first in the Roman Curia and then as pope, for almost forty years (Mr. Hatch is too much the professional writer to bore the reader with any tear-jerking scenes from the pope's childhood, and that era in Montini's life is covered in an early and blessedly brief chapter). An understanding of those events is necessary to an understanding of Paul for, as Hatch points out, it is history that has made of the pope the man that he is--the cautious, deliberate, diplomatic, unhurried and thoroughly devoted pontiff who has, in the happy expression of a cardinal-elector, ""Pacelli's brains in Roncalli's head."" Though Hatch obviously is an admirer of Paul, he is not for that reason uncritical; though he is reverent, he does not hesitate to call a spade a spade when dealing, for instance, with a curial official's unabashed political wheeling-and-dealing during a preliminary address to the electoral conclave; though his material is, for the most part, not original, the synthesis he has achieved makes the whole much greater than any of its parts. Paul VI not only the finest work on Paul, but it is also Hatch's best book. It should have enormous popularity among Catholic readers, and will be an indispensable addition to libraries both public and private, Catholic and general.