Henri Troyat's biography of Alexander has completely won me over. I opened it in no mood to refight long-ago wars or cope with complicated Russian names. But Alexander of Russia: Napoleon's Conqueror (E.P. Dutton, $17.95) turns out to be more enthralling than most of the novels I've read lately. I can forgive Troyat for a long battle or two, and when I forget who is who, an efficient index comes to my rescue.
Napoleon said of Alexander, ''No one could have more intelligence than the Emperor Alexander, but I find that there is a piece missing in his character, and I cannot discover what it is.'' It's the search for that piece and for the reason it is missing that makes this book so fascinating - and the subtitle for the French edition (published by Librairie Flammarion last year) - ''Le Sphinx du Nord'' - so much more appropriate.
The mystery of the missing piece must have something to do with the Emperor's bizarre upbringing. Almost as soon as he was born, his formidable grandmother, Catherine II, snatched him out of his mother's arms, called him ''the future wearer of the crown'' (bad news for father Paul), and started training him to be her successor. Hard leather pillows instead of a soft cradle to sleep on, cold baths, and cold rooms were just a few facets of her education system.
Pouring in the ideas of liberty from writers like Rousseau and Locke and his Swiss tutor, Laharpe, also played a part in the future Emperor's training. Then there were visits with his out-of-favor father, visits that Alexander found strangely appealing - ''strangely'' because Paul ran a Prussian state within the state dedicated to tough, unreasoning, unreasonable military discipline.
As for Catherine's behavior toward the boy, it was pure confusion (''Now the beribboned cap of grandma, now the bronze helmet of Bellona'').
To muddle young Alexander still further, the arrival of aristocrats escaping the guillotine cooled Catherine's enthusiasm for liberty and equality. The bust of Voltaire was exiled to the attic. And Catherine's young lovers soured Alexander on his grandmother and all she had tried to teach him.
But what he did learn and practice all his life was the art of switching - or pretending to switch - loyalties. Apparently he became so adept at talking out of both sides of his mouth that he deceived even himself. For instance, he could argue for freedom of the individual while he instituted the most hateful of systems, the military colony. Under that scheme, whole villages and every aspect of a peasant's life were governed by a brutal discipline. It was the army that dictated who should marry whom, how many offspring they should have. Even small children were forced into uniform. (''Only a few old women wept,'' the Czar was told). Protests were met with barbaric cruelty.
''He loved liberty'' as a topic of conversation, Troyat tells us, but the ''beauty of the idea lay in the very impossibility of making it a reality.'' In fact his character was so complex, the events of his life so dramatic, he might have been invented by Shakespeare.
My high school history teacher once complained that the only fact every member of her class got right was that ''Louis Napoleon could slice ham thinly.'' The habit has clung, and not even this book with its splendidly told segment of history has broken it. The passages I remember most vividly are those that give the past a human face. Most of them leave a peculiarly poignant taste.
For instance the officers who murdered Czar Paul first hoped to persuade him to abdicate. He shouldn't be governing millions of men, they told him, adding the strangely gentle rebuke, ''You make them unhappy. . . .''
Napoleon's way with royalty sticks in my mind. For instance, when King Maximilian Joseph dared to raise his voice during a ceremonial gathering, he got an awful rebuke from the former corporal: ''Hold your tongue, King of Bavaria!'' And when Frederick William III appeared in his splendid Prussian uniform, Napoleon put him down with an ironic ''How do you manage to button so many buttons?''
There's an unforgettable account of the Russians retreating from Moscow with the French at their heels: ''. . . the procession went on, a broad river of haggard faces and dusty greatcoats. . . . One might have thought two allied armies were marching together through a conquered city.''
But the passage I found most fascinating is not anecdotal at all, but perhaps , just perhaps, it is not too Pollyannaish to find hope in it for all voiceless peoples. The author is discussing how, after Napoleon's conquest of Moscow, support for the Czar came from a most unexpected source - the people - ''the obscure Russian multitude which had no means of expressing its views on affairs of state.'' Troyat suggests it might even have dictated the Czar's conduct.
''It was a miracle of spontaneity, of illegality almost, a mysterious plebiscite without ballots, a word of hope flying from mouth to mouth. For the first time the autocrat . . . felt himself borne forward by an irresistible mass movement . . . . With a mixture of happiness and anxiety, Alexander sensed that the Emperor of Russia was about to become the Emperor of the Russians.''