Bob Crane's last appearance as Dr. Dave Kelsey.
Shelly Fabares is credited with a guest shot in this episode. However, for the first and only time in this series history, she appears in film from past episodes and not actually 'in' the present. Fabares was busy with her own career outside of the series, but did appear in several episodes after leaving at the end of season #5. She appears in 4 season #6, 3 season #7 (#5, 15 & 30) and 1 season #8 episode (#13). Fabares left the series under good terms with Reed and her husband who owned its rights and had considerable say. Reed had encouraged her to move on before her 'career passed her by'. Her guest shots after season #5 (total of 8) were all scheduled to work around her other acting jobs and were never filmed out of formal sequence to accommodate her.