It is with profound sadness that we report the passing of Arnold Caplan, Ph.D. Dr. Caplan was an ICRS member from 2005 and was an ever present faculty participant at most of our summit and world congress meetings where he always asked the most scintillating questions leading to some of the most memorable and entertaining scientific debates I can recall. Dr. Arnold I. Caplan, 82, of Cleveland, passed away peacefully on Jan. 10, 2024, with his family lovingly by his side.