Curricular peer mentoring is a programmatic approach to enrich student learning and engagement in postsecondary courses in which instructors welcome a more experienced undergraduate student into a credit course they are teaching. The student then serves as peer mentor to the students enrolled. Peer mentors can provide a variety of peer-appropriate, course-specific mentoring, tutoring, facilitation and leadership roles and activities that complement the roles of the course’s instructor and teaching assistants both in classroom settings and beyond. A program provides training and ongoing support for a larger number of peer mentors and instructional teams and manages recruitment and program research and quality. This volume provides research findings, definitions, theories, and practical program descriptions as a foundation for program development and research of undergraduate curricular peer mentoring programs in higher education. This work builds on a long history of higher education program development and collects a significant amount of literature that has previously been scattered.