A slightly odd but ultimately very satisfying biography of a man who, in terms of political and historical impact, has been called ``the dominant writer of this century.'' George Kennan described The Gulag Archipelago as ``the most powerful single indictment of a political regime ever to be levelled in modern times.'' The irony is that the indictment came not from the West, but from a heroic survivor of the Gulag. It is the particular merit of this book that it shows such an understanding of the qualities that were required to survive the camps, to write with such demonic intensity, to fight against the constant threats and surveillance of the KGB, and to make no compromises with the truth. He and his wife solemnly agreed that they were prepared to sacrifice their own lives and those of their children, rather than betray what he had written. Such a man, as the noted novelist Thomas (The White Hotel, 1981; Lady with a Laptop, 1996; etc.) writes with delicate irony, ``could not also be your clubbable nice guy from next door.'' Without stinting the importance of what Solzhenitsyn did, Thomas gives a just appraisal of the human cost to those with whom he worked, particularly his first wife, of that total dedication. He also brings up-to-date the incomparable 1984 biography by Michael Scammell, and through interviews with Solzhenitsyn's first wife and access to material that has recently become available, including KGB files and debates in the Politburo, adds new and important material. The value of the book is lessened, however, by its heavy reliance on Scammell, its occasional ``imagined'' scenes and its crude Freudian analogies (Solzhenitsyn's supposedly ``anal'' temperament). Somewhat overwritten at the start (Dzerzhinsky, the first head of the Cheka, is described as ``goatee-bearded El Greco of terror, death's Stakhanovite''), it becomes simpler and better written as it goes on. A sympathetic and judicious appraisal that will deepen the understanding of this remarkable man.