Excerpt from Warlords by Simon Berthon, Joanna Potts, plus links to reviews, author biography & more

No one was going to restrain him over Poland and his generals had told him he must attack before the autumn rains came. Only one thing stood in his way: Britain and France had said they would go to war for Poland, raising the specter that the Soviet Union might also turn against him and propel him into a war on two fronts. This was the very thing imprinted in Hitler’s mind as having helped to lose Germany the First World War 20 years before.

Now in the pure air of the mountains, Hitler began to think the unthinkable—a pact with his greatest ideological enemy. In August 1939 he put out feelers to Moscow.

Not surprisingly Stalin was deeply suspicious of Hitler’s approach. He kept him waiting, spending hours reading Mein Kampf, Hitler’s autobiography and manifesto written fifteen years before, underlining key passages; among them Hitler’s views of the early Bolshevik leaders, men like Stalin himself: "Never forget that the rulers of present-day Russia are common blood-stained criminals, that they are the scum of humanity."

But Stalin could see that Hitler was now desperate for a deal and offering to send his foreign minister, Joachim von Ribbentrop, to Moscow. The British and French, by contrast, who were also courting him, had only managed to send a delegation of generals and admirals to Moscow. Stalin decided that Hitler’s offer was too enticing to resist and invited Ribbentrop to Russia. Goebbels, aware of the fearful prospect of a two-front war, noted in his diary: "Non-aggression pact with Moscow perfect. Ribbentrop in Moscow on Wednesday. That is something! We’re on top again. Now we can sleep more easily."

On 23 August Ribbentrop landed in Moscow. Shortly after midnight on the morning of the 24th the Nazi–Soviet pact was signed and with it a secret protocol under which Germany and Russia would carve Poland into two. Hitler phoned Ribbentrop: "This will hit like a bombshell." But as Goebbels noted, it was not strength but fear of Stalin knifing him in the back that had forced Hitler into history’s biggest U-turn: "The Führer believes he’s in the position of scrounging for favours and beggars can’t be choosers. In times of famine the devil feeds on flies."

In the Kremlin, Stalin proposed a cynical toast to Ribbentrop and the pact with the Nazis: "I know how much the German nation loves its Führer; I should therefore like to drink his health."But like Hitler, Stalin was also acting from fear, in his case that Hitler would attack him. That evening he told his inner circle: "Of course it’s all a game to see who can fool whom. He thinks he’s outsmarted me but actually it’s I who’ve tricked him." There was a curious postscript to the celebrations. Hitler had sent his personal photographer, Heinrich Hoffman, to film Stalin’s earlobes to see whether they were "ingrown and Jewish, or separate and Aryan." They were separate; Stalin passed Hitler’s test.

Stalin had found a bedfellow for whose cunning he had held a long and sneaking admiration. Back in 1934, he had observed Hitler eliminate his rivals within the Nazi party in the so-called night of the long knives and remarked: "Did you hear what happened in Germany? Some fellow that Hitler! Splendid! That’s a deed of some skill!" Hitler had felt no such mutual admiration. In his early years in power he was set on the dreams of Mein Kampf: an alliance with Britain’s sea empire while he expanded to the east and built his German land empire on the continent. Only when that plan had clearly failed did Hitler begin to see in Stalin someone with whom he might one day do business.

Stalin was the first of the two to be a mass murderer. In May 1937 as his terror began to move into top gear, he compared his victims with the boyar landowners massacred by Ivan the Terrible 400 years before: "Who’s going to remember all this riff-raff in ten or 20 years time? No one. Who remembers the names now of the boyars Ivan the Terrible got rid of? No one." A week before he invaded Poland, during a conference with his generals Hitler made an eerily similar remark: "Genghis Khan had millions of men and women killed by his own will and with a gay heart. History sees him only as a great state-builder. … And who, after all, speaks today of the annihilation of the Armenians?"

Reprinted from Warlords, Copyright 2006. Reprinted by permission of Da Capo Press.