A few months ago, Timothy Ferriss, a self-help author, threw himself a party in San Francisco, where he lives. Officially, it was not a celebration for his most recent book, "The 4-Hour Body: An Uncommon Guide to Rapid Fat-Loss, Incredible Sex, and Becoming Superhuman," which came out in December and is already in its eleventh printing. In the book, Ferriss tells his readers, "Hack yourself," and presents them with hundreds of "scientific rules for redesigning the human body": bathing in ice to lose weight, eating organic almond butter on celery sticks to treat insomnia. Nor was the party meant to mark the enduring success of his first book, "The 4-Hour Workweek: Escape 9-5, Live Anywhere, and Join the New Rich," which is still on the Times' business best-seller list after four years. That book counsels readers to limit their newspaper reading to the headlines visible from vending machines and to outsource the management of their calendars and finances to a remote personal assistant in Bangalore.