For those Isaac Asimov fans who wonder if two long, detailed volumes of autobiography and a book of memoirs might have left any stone unturned, here is a largely mundane collection of comments to peruse. Stanley Asimov, Isaac's younger brother who worked for 40 years for Newsday until his death last month, has culled comments from thousands of notes and letters, most written between the mid-1960s and 1992, when Isaac died. Stanley has organized the text by subject, with, for example, one chapter devoted to fans, one to travel (which Isaac abhorred), and three to "science fiction friends." Letters and excerpts (it is impossible to tell which is which) obediently keep to their designated subjects; thus, not surprisingly, selections tend to be brief a few paragraphs or even, occasionally, only a sentence or two and give the text more the feel of a reference book of quotations than a life in letters. Occasionally such brevity leads to insipidity, as when, in a chapter on writing, Isaac's first entry says, in its entirety, "I find mysteries entertaining." Some letters refer to incidents already familiar to Asimov fans: One recounts Isaac's concocting of a humorous little verse while on the operating table for thyroid cancer an event also discussed both in his autobiography and his memoirs. Although sometimes informative, Stanley's comments can also be merely organizational. When Isaac says that his alma mater, Columbia University, "always seemed a little unhappy that I was there," Stanley gives no hint of his brother's sense of not quite belonging or the effort it took him to get into graduate school in chemistry. A journalist very nearly succeeds in producing a book devoid of news.