Auschwitz is the focus, merely, for another attempt--like Waiter Laqueur's The Terrible Secret (1980, p. 1556)--to answer the general question ""of how and when the Allies learned of the Nazi extermination of the Jews"" (and how they did, or didn't, respond)--plus the rather different question, addressed in detail in Bernard Wasserstein's recent Britain and the Jews of Europe, 1939-1945, of why the Allies refused a Jewish appeal to bomb Auschwitz in 1944. The new factor is Gilbert's identity as a multi-volume Churchill biographer--with no more evident access to key papers, however, than Laqueur or Wasserstein, and with a certain protectiveness toward the Churchill government. On the ""how and when""--through the crucial years of '41 and '42--Laqueur looks harder, tells less, and says more. On Auschwitz, Gilbert stresses how little it came to attention, early on, and the impediments to knowledge of it; Laqueur stresses its gulag-like size and scope, and the impossibility of keeping its operations secret. Laqueur is far clearer, overall, on the widespread knowledge of the ""final solution"" by the end of '42; on the diverse, unofficial routes through which information traveled; on how little was done. Gilbert concentrates on the transmission of news through regular channels, and the responses thereto, which ultimately led to the condemnatory UN Declaration of December 1942. Between '42 and '44, Gilbert documents what is generally known--the Allied failure to put together the available information, specifically now about Auschwitz, into ""a definite and detailed picture""; but, as he and others agree, little could have been done about it during those years. (Such is not quite true of the situation of the Jews elsewhere--another reason the Auschwitz focus is distortively limiting.) We come, then, to the proposed, then-feasible '44 bombing of the railroad lines to Auschwitz, or the gas chambers and crematoria, which was shelved by the British (to whom the appeal was made) and dismissed by the Americans (whom they consulted)--though the latter is not apparent from Gilbert's account. Here, Wasserstein strikingly lays out the evidence and forcefully assigns responsibility--while Gilbert trails off into emotion-stirring testimony on the opportunity lost. It's a wordy, waffling book--with some fresh detail but no firm or pointed conclusions.