Cliff Robertson was a well-known and well-respected actor for many decades. I can think of many favorite performances of his. Charly, My Father's House that I at an early age recognized as a tour-de-force as the roles switched between Robert Preston and Cliff Robertson but was perhaps under-rated because it was a TV movie, The Honey Pot, and many of his television roles (Outer Limits, Twilight Zone, etc.)

Obituary from Washington Post.

SRS