Remember Nikita Khrushchev? He was the avuncular-looking Soviet leader who followed Josef Stalin and preceded Leonid Brezhnev.

(Don't write or e-mail me about Georgy Malenkov. His reign was too brief -- March to September 1953 -- and he never managed to consolidate power.)

		"LENIN, STALIN AND HITLER: THE AGE OF SOCIAL CATASTROPHE" By Robert Gellately Knopf ($35)

By Soviet standards, Khrushchev was a sweetheart. While Lenin oversaw the deaths of hundreds of thousands and Stalin liquidated millions, Khrushchev's victims can be counted in the thousands.

During the purges of the 1930s when "Old" Bolsheviks, suspect nationalities and entire social classes were exiled or murdered, Khrushchev became one of Stalin's "enthusiasts for terror," historian Robert Gellately writes.

Ordered to identify 35,000 enemies of the state, Khrushchev reported to Stalin that within two weeks he had detained 41,305 "criminal and Kulak elements." He personally selected 8,500, or about 25 percent, for execution.

Compared to how Stalin dealt with ethnic Poles living in the U.S.S.R., Khrushchev appears fastidious. Of the 140,000 Poles Stalin had arrested in summer 1937, 111,000 -- 80 percent -- were executed.

Gellately's well-written history contains many examples of such depressing statistics from the period between 1914, when World War I began, and 1953, when Stalin died.

Almost 89 years after it ended, World War I remains an inexplicable catastrophe. The conflict seemed to grow in intensity as it lost military purpose. It concluded with the destruction of four multi-national empires and the deaths of 13 million soldiers and civilians.

After such a cataclysm, what could make things worse? Lenin, Stalin and Hitler each found a new path, Gellately writes.

Lenin and his Bolsheviks took control of Russia in October 1917. By August 1918, Lenin had issued orders for mass terror against "kulaks (wealthy peasants), rich men, bloodsuckers." Within months, his new secret police, called the Cheka, had carried out more political executions than czarist officials had performed in decades.

Declaring himself the heir to Lenin, Stalin maneuvered himself to the top job in the "provisional dictatorship of the proletariat and peasantry."

Seeking to consolidate his own power and protect the Soviet state from some real and mostly imaginary enemies, Stalin counted his potential foes in the millions. He ordered their arrest, torture, exile and execution in similar numbers.

Gellately reports that until the start of World War II, Hitler simply was not playing in the same league as Lenin and Stalin. What he calls Hitler's "consensus dictatorship" was based on mass public support, achieved through a combination of finely calibrated terror and material payoffs.

During the mid-1930s, German concentration camps held a few thousand political prisoners; executions were in the hundreds.

Hitler's decisions to go to war in the East, first against Poland, then against the Soviets, changed the paradigm. The battle against the Jews, the Bolsheviks and the Slavs was a death struggle without rules, he told his generals. Execution specialists, using guns and poison gas, were aided by a compliant German army and local collaborators.

The number of Hitler's victims between 1939 and 1945 grew into the millions.

When he spied "Lenin, Stalin and Hitler" on my desk, a colleague asked, "Well, who was the worst?" While offering no easy answer, Gellately settles on Hitler. That's a judgment with which I concur.

But to paraphrase Tolstoy, each of Europe's most monstrous 20th-century dictators was awful in his own way.