A welcome start toward bridging the gap created by the ""chrysanthemum taboo"" (against reporting anything critical of the emperor) with fresh, unflinching perspectives on imperial institutions, the erstwhile Son of Heaven, and his times -- known in-country as the Sh"wa (roughly, enlightened harmony) era (1926-89). Drawing on papers prepared by the emperor for use if he were called to testify at the war-crimes trials held after V-J day, as well as on the recollections of top aides, historian Irokawa (Tokyo Univ. of Economics; The Culture of the Meiji Period, not reviewed) conducts a critical audit of actions taken (or not) by Hirohito at critical junctures. By way of example, he concludes that the putatively peace-loving head of state could have taken a far stronger stand against Japan's aggression in China during the early 1930s. In like vein, Irokawa puts paid to the agreeable fictions that the dynast played a limited role in his military's prosecution of WW II and that, in the wake of two atomic bombings, he decided to surrender for love of the people. After Dai Nihon's defeat, the emperor's sociopolitical role went through several transitions. With Japan's emergence as an economic superpower, to illustrate, the merely mortal monarch and his family (enjoying resplendent lifestyles in a new palace) became icons of upward mobility. Covered as well are the back-channel deals Hirohito was willing to make with the Allies on radical labor unions, Okinawa, and other substantive issues to preserve the national polity (i.e., his hereditary imperial office). Without ever launching into shrill tirades the author makes clear that Hirohito was a culpable co-conspirator in his country's ill-fated military adventures and a passive beneficiary of its remarkable recovery. Despite a translation that can most charitably be described as graceless, an illuminating take on a consequential 20th-century figure who has been overdue for a full accounting.