Del Close (March 9, 1934 – March 4, 1999), along with Keith Johnstone and Viola Spolin, is considered one of the premier influences on modern improvisational theater.

An actor, improviser, writer, and teacher, Close had a prolific career, appearing in a number of films and television shows. He was a co-author of the book Truth in Comedy along with partner Charna Halpern, which outlines techniques now common to longform improvisational theater and describes the overall structure of “Harold” which remains a common frame for longer improvisational scenes. His favorite framework for comedic storytelling was the structures of Wagner’s Ring Cycle.