IN his autobiography, "Speak, Memory," Vladimir Nabokov characterizes the outline of his life history in terms of Hegel's model of thesis, antithesis, synthesis: an idea or theme that generates its opposite, which in turn points the way to a fresh combination.For Nabokov, the oldest child of a wealthy and distinguished family, his first 20 years in Russia (1899-1919) constitute the thesis. The following 21 years of emigration and exile in Europe (a Cambridge University education, 15 years in Berlin, flight to France in 1937) are the antithesis: a time of loss, hardship, and nostalgia, during which he launched upon his career as a Russian author. Beginning anew in America at the age of 40, still facing financial hardships but delighted with the free and easy outlook of Americans, Nabokov found his "synthesis" - and the necessary impetus to make the momentous switch from writing in Russian to writing in English. Brian Boyd, a lecturer in English at the University of Auckland, New Zealand, has divided his massive and masterly biography of Nabokov into two volumes. The first (published in 1990) covered the Russian-speaking years: Nabokov's serene and happy childhood, his difficult years of exile, his Russian-language writings ("King, Queen, Knave,The Defense," "Laughter in the Dark,The Gift"), his early romances, and his marriage to the beautiful, highly intelligent woman who devoted herself to fostering his talent. In the second and final volume, "The American Years," Boyd tracks the less dramatic but no less remarkable second half of Nabokov's life, including the scandalous success of "Lolita," the critical success of "Pale Fire," Nabokov's famous friendship - and subsequent feud - with the curmudgeonly American man of letters Edmund Wilson, and the mixed reception accorded some of the later works, like "Ada" and "Look at the Harlequins!" An apolitical man whose outward life was shaped by the forces of politics, Nabokov revered the example of his father, an outstanding Russian liberal murdered by right-wing Russian monarchists who were trying to assassinate someone else. Nabokov's younger brother Sergey, an outspoken opponent of the Hitler regime, died in a Nazi concentration camp. Nabokov did not like politics, but as a Russian immigrant, he was expected by the American colleges and universities that offered him ill-paying, part-time teaching positions to keep students informed of the latest developments in the literature of America's newfound wartime ally, the Soviet Union. His refusal to teach the works of writers he regarded as crude propagandists made it harder for him to find a full-time position. But as much as he despised communist hacks, he also hated being lumped together with the motley crew of die-hard czarists, Russian Germanophiles, and philistines distressed at losing their material possessions to the Revolution. What he most valued about democracy is the freedom it gives individuals to take part in politics or ignore it as they choose, without fear of repression or reprisal. "Democracy," wrote Nabokov, "is humanity at its best, not because we happen to think that a republic is better than a king and a king is better than nothing and nothing is better than a dictator, but because it is the natural condition of every man ever since the human mind became conscious not only of the world but of itself." Boyd's subtle and sympathetic account of Nabokov's political views is matched by his treatment of other aspects of his subject's life and work, whether he is dealing with Nabokov's lecturing methods, his stringent views about literature (he looked down on almost everyone but Shakespeare, Tolstoy, Pushkin, Proust, and himself), or his lifelong devotion to the study of lepidoptera (he is credited with discovering several new species of butterfly). Gracefully blending biography with literary criticism, Boyd offers excellent explications of Nabokov's works, from the scarifying political/philosophical parable "Bend Sinister" (1947), to the poignantly comic misadventures of the Russian emigrPnin" (1957), from the sensationally best-selling "Lolita" (1955), to the dazzling labyrinth of poetry and prose that is "Pale Fire" (1962), which Boyd thinks "may well be the most perfect novel ever written." He also mounts plausible and intelligent (if not alway s persuasive) defenses of later works like "Ada" (1969) and "Look at the Harlequins!" (1974), where Nabokov's penchant for puns, riddles, and parody had become so pronounced as to leave many former admirers more annoyed than amused. Just as Nabokov's writings have often been criticized as overly cerebral and ingenious, Nabokov himself has been charged with snobbery. Boyd tackles these questions forthrightly and perceptively: He reveals the passion and tenderness that infuse the literary brilliance, the devotion to high aesthetic standards that had very little to do with the snobbery of class. We still might object, however, that it is all very well to berate Dostoyevsky, Mann, Gide, and Balzac as being inferior to Shakespeare and To lstoy, but that there is a great difference between aspiring in one's own work to the highest category and implying, as Nabokov seems to have done, that one is of the highest category. "Pale Fire" is no "War and Peace." What Boyd does, very effectively and often rather beautifully, is to put all of the various aspects of Nabokov's life and work into a spacious context - one that has sufficient height, breadth, and profundity to illuminate what is best about Nabokov. He portrays a man who grappled continually with the essential metaphysical issues of time and timelessness, the world we know and the unknown world we may infer from its traces in the design of this one. Boyd's Nabokov is the man whose voice we hear in the opening passage from his autobiography, "Speak, Memory" (1951): "The cradle rocks above an abyss ... common sense tells us that our existence is but a brief crack of light between two eternities of darkness.... Nature expects a full-grown man to accept the two black voids, fore and aft, as stolidly as he accepts the extraordinary visions in between. Imagination, the supreme delight of the immortal and the immature, should be limited. In order to enjoy life, we should not enjoy it too much. "I rebel against this state of affairs. I feel the urge to take my rebellion outside and picket nature." Whatever place Nabokov may eventually occupy in the pantheon of literary history, this sensitive, intelligent, well-written biography makes a strong case for him, as a man and as an artist. It is hard to imagine a better treatment of Nabokov than this one.