ISAAC ASIMOV was his own book-of-the-month club. Between 1950, when Doubleday published his first science-fiction novel, ``Pebble in the Sky,'' and his death in 1992, Asimov wrote more than 470 books - both fiction and nonfiction - on every topic imaginable. To be fair, more than 100 of those volumes were anthologies that Asimov merely edited or coedited. Still more were collections of his stories and essays that had been previously published in magazines or newspapers.
Nevertheless, Asimov remains one of the most prolific writers of the 20th century - a distinction he achieved working on his own, without the help of a research or support staff.
Now, posthumously, Asimov has added to his list of books a new autobiography. Called simply ``I. Asimov: A Memoir,'' this book refrains from the relentless month-by-month sequential account that characterized his earlier two-volume effort, and instead describes Asimov's life as a whole.
Asimov wrote most of ``I. Asimov'' from his hospital bed during the first few months of 1990. The author thought that he was about to die and his second wife, Janet, demanded that he write a subjective account of his life. Everybody would be interested, she assured him.
``I didn't really believe any of this,'' he writes. ``I am not a deep philosopher and I can't make myself believe people are dying to hear my thoughts. However, I know that I have a pleasant writing style and can keep people reading, whatever I write. And I also had the sensation that I was racing death. And, as ever and always, I wanted to please Janet.''
What he created is a marvelous story that traces his life from his beginnings as a poor Russian immigrant in Brooklyn, his unpleasant experience in the United States Army in 1946, and his years as a chemistry graduate student, a professor, and finally as a successful author.
Is the ``Great Explainer'' successful in explaining his own life? Absolutely. With his easy-to-read writing style that he says took him years to develop, Asimov's pen cuts straight to his inner core, baring his thoughts and feelings, portraying himself as a good-natured, kind-hearted man. Asimov is blunt in acknowledging his faults - an ego the size of the Empire State Building and a tendency to keep track of those with whom he had disagreements. Asimov's relentless score card of who was right (almost always he) and who was wrong does detract from the volume.
Child prodigies and their parents are likely to find more of interest in ``I. Asimov'' than the author's science-fiction fans. Although he spends many pages writing about his friends in the science-fiction community, the true value of Asimov's insight is his reflections on his life - and, in his mind, Asimov was first a genius, second a prolific writer, and only thirdly a sci-fi writer.
Asimov tells the reader repeatedly that his life would have been easier if he had learned to submerge his ego and get along with others. ``It really puzzles me as I look back on it that I didn't make a greater effort to placate the powers that be,'' he writes. Indeed, it was this inability to get along with others that forced Asimov out of academia and into the solitary life of a freelance writer.
Edited by Janet Asimov, ``I. Asimov'' is a captivating volume. And lest the world think it has heard the last of Asimov, fear not: Doubleday is publishing a book of his letters in the fall of 1995.
* Simson L. Garfinkel is a freelance writer who specializes in science and technology.