Finding the hidden foundation of change: The legacy of Dr. Charles Gelso.

This article describes the author's perceptions of the value and legacy of Charles Gelso's ("Charlie's") work and his contributions to the field of psychotherapy research, practice, and training. Charlie's major theoretical and empirical contributions on the therapy relationship, most notably the tripartite model and the real relationship, and the research-training environment are discussed, alongside personal reflections of Charlie as a mentor. Lessons learned and suggestions for carrying his legacy forward, as we continue to advance psychotherapy research, practice, and training, are suggested. (PsycInfo Database Record (c) 2026 APA, all rights reserved).