GENERATIONS EXPERIENCE psychic moments, signal events which end one era and father the next. Plymouth Rock, Lexington, the Alamo, Lincoln's assassination and the Maine are the buoys of a common American heritage whose more diffuse streams leave less delible impressions. The Japanese attack on Pearl Harbor falls among this select group of incidents about which we constantly crave more knowledge.

Pearl Harbor stunned all Americans, but none more than that generation of professional naval officers who saw their wartime achievements bracketed by the opening attack and the noisy postwar investigations. The late Rear Admiral Edwin Layton fell into this cohort. Earning his commission in 1924, Layton became one of a small number of Japanese language specialists and served from 1940 to 1945 as Pacific Fleet intelligence officer. In retirement after 1959, Layton "seethed" over the "cover-up in Washington" which had resulted in the relief of the prewar fleet commander, Admiral Husband Kimmel. Gordon Prange's At Dawn We Slept stirred Layton to begin this memoir which John Costello completed after the admiral's death.

Although its prose is in the first person, the text frequently strays so far from matters with which Layton was intimate that annointing the book as either memoir or history abuses both terms.

In passages that drip with the breathless and dangerous phrase "we now know," Costello pursues three theses. First, he argues that President Franklin D. Roosevelt promised in late 1941 to defend British territory if Japan attacked the Empire. Next, he insists that "plotters" in Washington deprived Kimmel of intelligence which "would have" alerted him to imminent danger. Finally, Costello contends that admirals Joseph and John Redman misinterpreted Japanese intelligence before the Battle of Midway that was correctly analyzed by Commander Joseph Rochefort in Hawaii. After the battle, Costello concludes, the Redmans deprived Rochefort of a medal he deserved and conspired to send him to sea.

TO SUPPORT these accusations, Costello dusts off some old canards and potboils some new evidence; most of the latter deserves more scrutiny than he invested. The litter of errors of fact in the text fouls most of the nesting interpretations. Costello presents no proof that Roosevelt ordered American forces to defend British territory. The charge of a prewar plot against the Pacific Fleet ignores the high state of alert of less exposed bases. Finally, Layton's appraisal of Rochefort's relief is supported only by hearsay and rests mostly on the animus of innuendo.

The publication of this book is a sad affair on two counts. It enhances the image of Pearl Harbor historians as quarrelsome cranks whose cottage industry survives on hot air. Costello's rendering also demeans the memory and achievements of a fine officer, who deserved more from the legatees of his remembrances.

To learn "lessons" from Pearl Harbor, as Costello unctuously tries, is a wearisome chore. Nothing is learned from either Prange's surety that his would be "the verdict of history" or from Costello's disingenuous argument that further study "is unlikely to alter the scene."