Abraham Morgentaler, M.D., is an associate clinical professor of urology at Harvard Medical School and the founder of Men’s Health Boston, a center focusing on sexual and reproductive health for men. He is the author of a number of popular books, including The Male Body and The Viagra Myth.

From a Harvard doctor and a leading expert on testosterone- the groundbreaking book that shows you have to reverse low testosterone and live your life to the fullest. Better sex. Increased vitality. Improved health. More muscle. Greater mental agility. These are just a few of the life-enhancing benefits of testosterone therapy for men with low levels of testosterone. If you’ve noticed a decreased in your sex drive; experienced erectile dysfunction; or felt tired, depressed, and unmotivated; this authoritative, up-to-date guide from an expert at Harvard Medical School will help you determine if you have low testosterone– a surprisingly common but frequently undiagnosed condition among middle-aged men.