Substance abuse is a complex issue that has extensive medical, social, legal and criminal ramifications creating repercussions through all social strata. Substance abuse could rightly be called "THE HIDDEN EPIDEMIC" as a serious public threat only when disastrous consequences are reported in the media. New ways of abusing and new substances of abuse evolve every day. Pickerill's words on the lack of time devoted to the prevention of Dental Caries would aptly apply for the prevention of Substance Abuse. This means we should start focusing more on the epidemiologic factors. Although reducing the burden of disease is one important call for us, tackling Substance Abuse at upstream level is the heart of public health approach. This book reviews and gives a bird's eye view of this 'public menace'. The book is a sincere attempt to meticulously compile the historical background, Epidemiology and public health impact of the various substances of abuse. This compilation will definitely give you concise and evidence based information about substance abuse and its impact on public health, both in the international and Indian context.