What begins as a titillating, tattling expose of Hugh Marston Hefner's private affairs turns into a straightforward, business-oriented biography, a major part of which is devoted to Playboy's formative years. Brady, one of the magazine's former associate editors, is merrily revelatory as he takes us on a guided tour of Hefner's Chicago mansion whose motto -- ""Si Non Oscillas, Noli Tintinnare"" (""If You Don't Swing, Don't Ring"") -- is inscribed on a brass plaque. It was there during the mid-'60's that the entrepreneur led a functionally hermetic existence ""working in his now-famous Brobdingnagian circular bed,"" surrounded by the latest in electronic gadgetry, TV cameras and mirrors (Hefner: ""I've got a kinky thing going, visually, while I'm having sex""). Rumors to the contrary, HMH is ""thoroughly heterosexual"" -- in fact, ""It is probable that Hefner has made love to more beautiful women than any other man in history."" Less interesting, though perhaps more accurate, is the story of a precocious youth with an I.Q. of 152 who began his own newspaper at the age of eight. Following his ""something of a mid-western wallflower"" pubescent years, Hefner joined the army and got hitched (to Millie) before gaining entrance into the publishing field as a cartoonist with bigger expectations. The author surveys the magazine through the years -- Playboy went both public and pubic in the '70's -- and up to its present preeminence as ""a Baedeker of savoir faire. . . a direct conduit to the psyche of America."" Hefner himself remains as paradoxical as ever -- a ""temperate and sometimes kindly man"" when not a ""ruthless monomaniac in his business dealings."" That complex yellow pajama-clad figure is a ""sensitive romantic"" in the opinion of a close companion; yet, ""all of the people he refers to as friends are merely vassals."" Although this is a prematurely ejaculatory version, such tularemia is often contagious.