What should be done? To the question that hung over 19th-century Russia and dogs the world today, Isaiah Berlin would answer, stand firmly uncertain. Russian-born and Oxford-bred, Berlin has almost single-handedly kept alive in the West a sense of the intellectual fervor and moral complexity of pre-Revolutionary Russian thought. In these essays of 30 years, he demonstrates, with the clarity, vividness, and precision he attributes to Tolstoy, that failure of the 1848 revolution in Western Europe forced Russian intellectuals, now isolated and insulated, "to develop a native social and political outlook," harsh, unsentimental, and ultimately uncompromising; that there exists "a great chasm between those who relate everything to a single vision. . . [and] those who pursue many ends" (in "The Hedgehog and the Fox," on Tolstoy's view of history); that Herzen and Bakunin, at one in elevating the ideal of individual liberty, divided irreparably on means, Herzen, "the sworn enemy of all systems" (and Berlin's greatest hero), holding that liberty is an absolute value not to be suppressed for the sake of future happiness or any other "huge abstraction." And, in "The Birth of the Russian Intelligentsia," he credits "the great Russian essayist Belinsky," hardly known in the West, with virtually inventing the kind of social criticism which enjoins art to be responsible to life--in the specifically Russian context, to set men free. Neatly to link Berlin's themes does not do justice, however, to the exceptional richness and suggestiveness of their development. Within a frame of reference that extends from the author of the Book of Job to D.H. Lawrence and Franklin Roosevelt, he exactly places the figures of his Russian protagonists; and each of them he portrays as an individual. Tolstoy "was by nature a fox, but he believed in being a hedgehog," and the conflict emerged in his unresolved (between determinism and free choice) view of history in War and Peace; the gentle, skeptical, tolerant Turgenev created, in Fathers and Children, the "brutal, fanatical, dedicated figure" of the agitator Bazarov; "Does he then symbolize progress?" Turgenev remained ambivalent, "the notoriously unsatisfactory, at times agonizing, position of the modern heirs of the liberal tradition"--to which Berlin wholeheartedly subscribes. An absorbing, arresting group of studies, and as important a book as will be published this year.