(written from a Production point of view)
Erman directed the Star Trek: The Original Series third season episode "The Empath". He helmed episodes of many television series and a number of TV movies during his 33-year career as a director. His credits include My Favorite Martian (starring Ray Walston), The Outer Limits (episode "Nightmare" featuring David Frankham, Willard Sage, Bernard Kates, John Anderson, Whit Bissell and Vic Perrin as the "Control Voice", written and produced by Joseph Stefano with make-ups by Fred Phillips and assistant direction by Robert H. Justman), Ben Casey, M*A*S*H and Roots (starring LeVar Burton, featuring Madge Sinclair, Thalmus Rasulala and music by Gerald Fried). He also worked as a production associate on The Outer Limits.
Erman was hired by co-producer Robert Justman, who worked as 1st assistant director and production manager on The Outer Limits due to his experience directing the aforementioned "Nightmare", which also featured aliens torturing captured humans in a dark and minimalistic setting. However, Erman was not entirely satisfied with the working conditions on Star Trek, and decided not to return to direct further episodes. (These Are the Voyages: TOS Season Three, pp. 240-241, 252)
He passed away at the age of 85, after a short illness on 25 June, 2021 in New York City.