Reading Moshe Lewin's "The Soviet Century" is very similar to struggling through the theological and philosophical writings of the emigre thinker Vladimir Lossky: Every few pages, one is forced to pause and ponder what just passed. Fortunately, many of the book's chapters are short (10 pages or fewer), allowing for frequent rest stops along the way.

So this weighty tome is not the right choice for those hoping for a quick, easy read while heading out to the dacha for the weekend. Nor should the title mislead those interested in a pop-history of the Soviet Union that starts with the storming of the Winter Palace and ends with the lowering of the red banner over the Kremlin. This is not a linear history, but, rather, a collection of themes, skipping from Josef Stalin's plans to acquire supreme power to discussions of Gorbachev rival Yegor Ligachyov and Brezhnev contemporaries Alexei Kosygin and Yury Andropov -- all before arriving at Vladimir Lenin more than halfway through the book.

"The Soviet Century" begins with a reminder, critical to Russians (and to citizens of the other post-Soviet republics, for that matter), that dismissing the Soviet experience as an anomalous interlude in Russian history is "utterly absurd." After all, Lewin writes, "Soviet Russia remains a weighty component of Russia's cultural and political tradition, which continues to influence the country to this day. ... Can this be ignored by anyone who is interested in their country's destiny and reflects on it?"

Certainly not. Without a full appreciation -- and, Lewin adds, a full understanding -- of the Soviet system, one can hardly make sense of Russia's present. The Soviet Union was not a temporary blip, an unwelcome interruption between a pre-Revolutionary past and post-Soviet future, but a juggernaut that rolled over everything in its path. Nothing was left unaffected, from political culture to economic infrastructure, language, religion and social habits. This book is a direct challenge to those who believe that the impact of the Soviet period can be minimized or exorcised and that either an utterly new path can be paved from its wreckage or a pre-Soviet path picked up again, like a lovingly restored chapel dwarfed by massive apartment blocks, after 70 years.

In coming to grips with the Soviet system, Lewin, a distinguished professor emeritus of history at the University of Pennsylvania, has taken advantage of the opening of the archives as well as the work of Russian scholars over the last decade to re-evaluate his own analysis and conclusions from the time when he saw "as through a glass, darkly."

Lewin does not attempt to link post-Soviet developments with their Soviet antecedents; the name Vladimir Putin doesn't appear even once in the book. But the reader cannot help but be struck by how much of what Lewin describes still resonates today: the political divide between those who wanted a strong state at any cost versus those who wanted the state, however weak, to benefit the greatest number of its citizens; the emergence of the security services as a major player in the economic life of the country; the use of compromising materials to dislodge rivals from power; and the question of reforming the bureaucracy.

No doubt, readers will be most drawn to Lewin's richly detailed depiction of the Stalinist system and of how Stalin concentrated all power in his hands, adopted a revolutionary alibi to legitimize his rule, and recast practical limitations as enemies who could be persecuted and scapegoated.

More interesting, however, are two later discussions of how subsequent leaders attempted to change the rules of the game and push the Soviet system in a new direction. In the first, Lewin describes how the post-Stalin regime attempted to deal with dissent, not via extermination but via prophylaxis -- by isolating and containing it. The same could be said for the semi-liberal, semi-authoritarian regimes of Eurasia, Asia and the Middle East today, which demarcate specific social spaces for freedom of expression while designating other venues off-limits.

Also illuminating is Lewin's discussion of the avalanche of urbanization that fundamentally transformed Russia in the years after Stalin's rule. Gone today are the idealized village scenes and picturesque 19th-century towns that crowded the pages of the pre-Soviet readers used at the after-school Russian classes I attended as a child growing up in California. Urbanization, Lewin points out, "engendered new conceptions of existence ... light-years away from the rural rhythms of traditional Russia." And it is because of urbanization that the Soviet legacy cannot be undone or reverted to the pastoral ideal.

While Lewin's book is serious and well researched, it will no doubt face tremendous criticism. Anti-Soviet circles in Russia and abroad will object to its lack of moral indignation at the excesses of the Soviet regime -- it is Lewin's opinion that "anti-communism is not historical scholarship" -- although I think that his bare-bones presentation of the facts allows readers to draw their own normative conclusions. One cannot read the NKVD's Order No. 00447, from July 1937, with its painstaking breakdown of exactly how many tens and hundreds of thousands of people should be shot and sent to labor camps, without a shudder.

Itar-Tass Russia was transformed by the shock urbanization that marked Stalin's rule.

But the real debate will come over Lewin's assertion that Stalinism is not the sum total of the Soviet experience and that the Soviet legacy should not be blackened as a whole by the brush of Stalin's brutality. As he notes, in the later Soviet period, political dissenters were more likely to receive a jail term than get killed. Even if this was still an injustice from the dissenter's point of view, it was a massive improvement from the perspective of history.

Lewin's research raises the critical question of whether the Soviet system, given time, could have evolved into something better. But it also stops short of full-blown nostalgia, pointing out that the Soviet Union failed to solve the critical issues that had plagued Russia since tsarist times and, instead, created a blocked political system "impeding any economic and social progress."

Whether or not one agrees with Lewin's analysis or conclusions, his central argument is inescapable: Russia cannot afford to quaff the waters of the river Lethe and search for peace and prosperity through historical amnesia. What replaces the Soviet system will still have to cope with Russia's burdens -- and Russia will be better off the sooner is comes to an honest reckoning of what the Soviet Union really was.

Nikolas K. Gvosdev is executive editor of The National Interest and a senior fellow for strategic studies at The Nixon Center.