The editors' goal in preparing the fourth edition of this introductory textbook was to provide a book that would clearly define the essence of recreational therapy as a health care profession. Thus, the book is focused on the purposeful use of recreation and leisure as interventions to enhance the health and well-being of clients whom recreational therapists serve. To emphasise this goal, the title used for this edition has been changed from "Therapeutic Recreation: An Introduction to Recreational Therapy: An Introduction". To accomplish their goal, the editors called upon leading authors to join them in writing chapters for this edition. Readers will notice that the list of authors includes some of the best-known experts in the profession and some of the rising stars of recreational therapy. Each author brings his or her expertise to providing the most current information in his or her area of specialisation. The contributions of each author make this fourth edition a truly unique work. Readers also will notice that two new editors have agreed to collaborate with the editors of the three prior editions of the book and to author chapters in their areas of expertise. Thus, this new edition benefits from having the best efforts of a team of editors and authors. Those reading this edition will find a continuation of the user-friendly approach employed in prior editions. Chapters begin with a list of learning objectives and end with a series of reading comprehension questions and a complete list of references. This edition also follows the tradition of prior editions in using the same format in every chapter devoted to a specific client population. This format includes a feature that has been appreciated in prior editions: a case study to illustrate the concepts in each chapter. A unique aspect of this edition is the inclusion of a chapter on the provision of recreational therapy for members of the military services as one of the specific client populations. Finally, the editors express thanks to the scores of individuals who appreciated the format and content of prior editions of the book and who encouraged them to prepare this fourth edition. Hopefully, this new edition will live up to their expectations and will further the practice of recreational therapy.