This 4th edition of the Guidebook for Clerkship Directors represents the collaborative effort of the eight member organizations of the Alliance for Clinical Education and reflects the knowledge and experience of its many authors, all of whom are devoted to medical student education. The Guidebook offers both new and experienced medical school clerkship directors high-level and often detailed information and guidance on the best ways to organize a clerkship, develop and evaluate a curriculum, implement that curriculum and evaluate the students performances within those curricula. Others interested in or already involved in undergraduate medical education will also benefit from the bookA1s content, with its focus on professional development and personal career development. In addition to updating the materials in chapters carried over from the 3rd edition, this edition adds chapters on advising and mentoring of students, nurturing professionalism, incorporating basic sciences into clinical experiences, developing residents as teachers, developing and teaching clinical reasoning, longitudinal integrated medical education, the fourth year and subinternships, simulation, and developing residents as teachers.