If someone asked me a year ago why I thought it was that men leave women and never come back, I would have said this: New Cow. New Cow is short for New Cow Theory, which is short for Old Cow-New Cow Theory, which, of course, is short for the sad sorry truth that men leave woman and never come back because all they really want is New Cow. But no one asked me then. If someone asked me now I would have a different answer. I would roll my eyes, look toward the ceiling, raise both hands and shake them toward the heavens the way old Italian women do, and say this: They will never make sense; you will never understand them. Welcome to the case file labeled "love" of one Jane Goodall--no, not the Jane Goodall, but a late-night TV producer who turns to the annals of animal behavior for an explanation when true love goes suddenly, inexplicably wrong. It began as a simple Cow meets Bull story: he was the young producer with the washboard stomach and the J-Crew good-looks, she the co-worker with her heart on the shelf. They met for drinks, fell in love, looked together for a cozy one-bedroom apartment on the Upper East Side, and then suddenly, in only the third month of their post-copulatory phase, Ray Brown was gone. Not gone gone, but lost to that jungle of unreturned phone calls known as unrequited love. So Jane Goodall, with the help of Freud, Darwin, and her own menagerie of lovelorn friends--a broken-hearted womanizer named Eddie, her best friend Joan, who for the past two years has been dating her boss, a man engaged to another woman, and David, who shares with Jane both a taste for good-looking men and a terminal case of bad luck--delves into the mystery of the male animal.