The use of social media around the world has exploded in recent years, with the number of monthly active users of Facebook and Twitter estimated to be one billion and one quarter billion, respectively. Physicians and medical trainees are among the users of social media, raising questions of how Facebook, Twitter, and other novel online tools may best be harnessed to further medical research, patient care, and educational pursuits. Because social media enables an immediate exchange of information and ideas around shared areas of interest, it has fostered communication and collaboration among a global network of researchers, clinicians, patients, and learners. Social Media in Medicine reviews a range of topics, from research ethics to medical education, and includes personal reflections by clinicians and learners that represent diverse opinions about the role of social media in medicine. The book is relevant to all healthcare stakeholders and will hopefully encourage ideas and questions to generate more research into the use of social media in medical research, patient care, and education. This book was originally published as a special issue of the International Review of Psychiatry.