THERE IS NO USEFUL purpose served in informing me that milk can be pasteurized by keeping it at 161 degrees Fahrenheit for 15 seconds; or that Wild Bill Hickock was originally called "Duck Bill" because of "his long nose and protruding lip"; or that the Empress Dowager of China had nails four inches long on some of her fingers. No purpose, that is, except that of pure entertainment, which is a lofty purpose indeed - made loftier, perhaps, by the cherished illusion that in gathering such trivia from Wallace pere and Wallechinsky fils I am learning something.

For those who share the curious idea that time spent acquiring useless information is somehow more morally uplifting than time spent playing cards or watching old movies on television or lying on a beach, The People's Almanac No. 2 , like its predecessor (from which it differs completely in content) and like its cousin, The Book of Lists , offers a plenitude of richly diverse satisfactions. One may learn, for example, about "a New England composer named Greeler" who set the entire U.S. Constitution, including the preamble and Bill of Rights, to music for the American Centennial. And considering that the work would take six hours to perform, the few seconds needed to read about it are probably the best way of getting to know it. A page later, there is the story of a mob in Erwin, Tenn. that lynched an elephant named Mary who had run amok and killed a man, and not long after that we encounter the ingenious William G. Hall of Shrewsbury, England, who committed suicide by boring eight holes in his head with an electric drill.

There are almanacs grimly dedicated to the conveying of useful information, such as the speed of light and the population of Switzerland. The People's Almanac No. 2 is not entirely uncontaminated with such material, but it strives nobly and with considerable success to temper such usefulness. The information on pasteurizing milk, for example, is contained not in an article on milk or on pasteurization, where a person of utilitarian motivation might find it, but in a short list of things that can be done in 15 seconds.

One thing that can be done in 15 seconds, by simply opening this book at random, is to learn something that you had not known before and that you are happier - if not better - for having learned. For example, (now opening book at random to page 903) that Sears Roebuck sold a 1902-model wood-burning stove (presumably cast iron; it weighed 415 pounds) for only $14.95.

The avid reader, appalled at the loss of a single second that might be devoted to soaking up such trivia, will find this compendium a delight even though it is a bit bulky to carry around for use in odd moments such as waiting for elevators. But it also has long sections for those who like to sit down and take the time to chew and digest some sustained reading. There is, for example, a splendidly miscellaneous 31-page section on human behavior that includes accounts of half a dozen intriguing experiments, a biography of Hermann Rorschach, a discussion of phrenology, a page and a half on the strange habits of some famous people and nearly two pages on the dreams of other famous people, over two pages on the psychological aspects of various colors and a brief but searching essay on what happens to us while we sleep.

For some readers, there will be a special cost-effectiveness in the opening essay in the human behavior section, which contains summaries of 16 popular self-help books, including How to Win Friends and Influence People, Games People Play, The Primal Scream, Winning through Intimidation and Your Erroneous Zones .

There are 31 other sections, dedicated with a similarly random zeal to such subjects as money, history, the universe, love and sex, communications media, lists (naturally), health, Americana, death, unexplained phenomena and other topics. One section is a collection of essays, including one on how close our society approaches that of Orwell's 1984 and another containing all the recorded words of Lee Harvey Oswald from the time of his arrest to his death (his final words were "at the present time I have nothing more to say to you.")

In many ways, the most interesting section of the book is the final one, which is composed of highly miscellaneous material sent in by readers of the first People's Almanac . These items range from an extended essay on the deficiencies of the standard typewriter keyboard to a suggestion that rape victims should prosecute their assailants for the more easily provable crime of indecent exposure.

Unlike most almanacs, which confine themselves unimaginatively to reality, this one also includes rather detailed biographies of Dr. Victor Frankenstein, Mary Worth, Mr. Spock of the starship Enterprise and several other "people who never were - yet live today." They coexist well with the biographies of such figures as David Rice Atchison, who may have been President of the United States for one day (March 4, 1849) because Polk's term had expired and Taylor refused to be sworn in on a Sunday.

This is, in sum, a most heterogeneous and unpredictable volume, certain to contain something to interest almost anyone who reads at all and likely to provide the true lover of serendipity and trivia with years of literary nibbling. It is the kind of book where one happily discovers Thomas Jefferson's recipe for vanilla ice cream on the same page with Toulouse-Lautrec's lemon pie. If it does not tell you the mean temperature of Cap d'Antibes in October (and frankly, I don't know whether it does or not), it is likely to make you forget that that's what you were looking for.