The generation that fought World War II is beginning to pass, and few remember much about the final year of the war with Imperial Japan except for the decision to use the atomic bomb. That choice has echoed through history without context, endlessly second-guessed, attacked and defended.

British journalist Max Hastings is all about restoring context in the 500 densely endnoted pages of Retribution: The Battle For Japan, 1944-45. As for the central (or, at least, tangentially related) question, he comes down clearly on one side. Hastings posits early:

“Most post-war analysis of the eastern war is a delusion that the nuclear climax represented the bloodiest possible outcome. On the contrary, alternative scenarios suggest that if the conflict had continued for even a few weeks longer, more people of all nations—and especially Japan—would have lost their lives than perished at Hiroshima and Nagasaki. The myth that the Japanese were ready to surrender anyway has been so comprehensively discredited by modern research that it is astonishing that some writers continue to give it credence.”

Despite the tremendous heroism of those fighting, few come off as pure heroes in the mess of war. Generals (particularly Douglas MacArthur) readily gave up the lives of their soldiers out of arrogance and ego. On the grand scale, Hastings argues the entire campaign to retake the Philippines had as much to do with MacArthur’s ego as military necessity. And on the micro level, MacArthur totally dismissed what turned out to be very accurate reports from intelligence operatives about Japan’s troop strength in the Philippines because it didn’t support his vision and he didn’t like intelligence officers.

But beyond applying context, Hastings also makes clear how casual the decision to use the bomb turned out to be in many key areas, including his assertion that top political leaders seemed only notionally aware of the atomic bomb’s uniqueness as a weapon. If that seems shocking in 2008, the decision to use the atomic bomb must be seen alongside events like the first firebombing of Tokyo, on March 9, 1945. Hastings follows one civilian family’s experience that night, when the air itself caught on fire over Tokyo, and when so many civilians burned and died and drowned trying to escape the conflagration. Hastings’ harrowing account of this family’s almost total devastation is followed by blunt statistics: “The 9 March 1945 American bomb attack on Tokyo killed around 100,000 people, and rendered a million homeless.” And, that was to be the beginning of many such raids on Japan.

But Hastings is not out to paint Imperial Japan in a sympathetic light. The systematic brutality, rape and genocide against the Chinese and other occupied peoples by Japan’s army is brutally documented as war crimes largely ignored by history in this part of the world. Hastings writes, “The Japanese, having started the war, waged it with such savagery towards the innocent and impotent that it is easy to understand the rage which filled Allied hearts in 1945, when all was revealed … War is inherently inhumane, but the Japanese practiced extraordinary refinements of inhumanity in the treatment of those thrown upon their mercy.” Hastings makes clear why the region to this day bears so much resentment toward Japan for failing to fully acknowledge their troops’ behavior in history books. In fact, Hastings dismisses almost all Japanese historical accounts of the war.

Hastings also offers a horrifying portrait of the Japanese leadership in place for the final year of the war. In Japan, he writes, “less able men, willing to obey without question even the most absurd instructions, held key postings. The indispensable qualification for high command was a willingness to fight heedless of circumstances, and to avow absolute faith in victory. The result was by the summer of 1944, many of those charged with saving Japan by their military endeavors possessed the hearts of lions, but the brains of sheep.”

The result was tremendous human slaughter as the war lurched toward its always inevitable conclusion: Japan could not win, and the Allies could not lose. The real issue to Hastings about the last year of the war is not so much the use of the atomic bomb, but why so many had to die in those months leading to its use. His answer is a thickly researched and rational presentation of war’s irrational thinking.