Internet has become an integral part of the life of millions of people in the Western countries and in the developing world. Millions of people search for mental health information on the Internet, and there is a lot. Multiple web sites offer a plethora of information on different topics. Recent research suggests that Internet may play a role in suicide prevention. At the same time, there is an increasing concern that Internet may promote suicidal behaviour. Some authors call Internet a double-edge tool. Internet providers try to seek a balance between preventing Internet-arranged suicides and safeguarding freedom of expression. The relationship between Internet and suicide is perplex. Understanding the impact of Internet on suicidal behaviour is an important challenge for future research. This book will contribute to this goal and will be of interest to clinicians, researchers, and the general public.