Sex therapist Bettina Arndt's new book is all about why sex matters so much to men. Over 150 men kept diaries for her, talking about what it is like to live with that constant sparking sexual energy-relentless, uncontrollable, all-consuming. Their painfully honest, confronting, often hilarious stories explain their quest for sexual adventure, their secret delights, sexual kinks and quirks, the thrill of giving pleasure and why some men turn to pornography.