It's been 50 years since Hugh Hefner took to his mansion in silk pajamas to woo and bed a bevy of bombshells. Now the American sexual revolution is as dated as a Playboy bunny suit, and Hef is as wrinkled as his sheets.

So how valuable can his Hef's Little Black Book be now?

Well, it may not hold much in the way of phone numbers, but this slim new release from HarperEntertainment ($19.95) gives away something far more valuable: Hef's point of view on seduction, love and how to choose the best pajamas.

Co-written with Bill Zehme, Hef's Little Black Book contains the king of swing's own words, connected by narration on Hef's life from Zehme. If it's sometimes as cheesy as a round bed in a wood-paneled room (note the many adoring pictures of Hef fondling blond babes), more often it imparts knowlege of women that only a man who's spent a lifetime studying them might glean.

Consider this: "The best line is really not a line. The best line is listening. That is to say: The best way of getting a woman interested in you is to be interested in her. Look for some kind of common connection."

Or this: "Who was it that said that five minutes after he had sex, he wished the woman would turn into a poker table and five of his buddies? I don't agree. . . . Cuddling is very important. . . . If it's the first time, then what is looked for afterward is something sweet and romantic and reassuring, just the way it was before sex."

The Hef that emerges from these pages is observant, honest, sweet and, OK, maybe just a little swaggering. Fifty years of fame will do that for a man.

And at age 78, a little Viagra doesn't hurt, either.