This publication provides a guide for STEM Education Centers (SECs) and Centers for Teaching and Learning (CTLs) to carry out a self-assessment process focusing on their role(s) in undergraduate science, technology, engineering, mathematics (STEM) education. These resources were developed to assist centers in framing their contributions to undergraduate STEM education based on a national-scale research project about the work of centers and their roles on campus. To effectively focus the use of these resources on centers' unique roles and priorities on individual campuses, we invite centers to consider their identity and how it overlaps with the goal of improving undergraduate STEM education. Centers may wish to revisit this during or after the self-evaluation process. Clarifying center identities in the undergraduate STEM education improvement space will be helpful in advancing the whole community, and build further opportunities for centers seeking to expand their work. [This content is provided in the format of an e-book.]