Anxious Americans have increasingly pursued peace of mind through pills and prescriptions. In 2006, the National Institute of Mental Health estimated that 40 million adult Americans suffer from an anxiety disorder in any given year: more than double the number thought to have such a disorder in 2001. Anti-anxiety drugs are a billion-dollar business. Yet as recently as 1955, when the first tranquilizer,Miltown,went on the market, pharmaceutical executives worried that there wouldn't be interest in anxiety-relief. At mid-century, talk therapy remained the treatment of choice. But Miltown became a sensation,the first psychotropic blockbuster in United States history. By 1957, Americans had filled 36 million prescriptions. Patients seeking made-to-order tranquility emptied drugstores, forcing pharmacists to post signs reading more Milt