Therapeutic letter writing has been viewed by psychologists as a powerful form of creative writing in health care settings. I explore the cultural contexts that have aided its popularization to shed fresh light on debates about its psychological function and efficacy. I draw on the sociologist Frank Furedi's analysis of 'therapy culture' to argue that contemporary ideologies of the vulnerable self have stimulated this practice, particularly in the form of letters written not-to-be-sent. I conclude by considering models of developmental letter writing that attempt to challenge these ideologies, including narrative therapists' provocative method of corresponding with clients.