(written from a Production point of view)
Olaf Pooley (born 13 March 1914; age 100)  is an English actor who portrayed the cleric in the Star Trek: Voyager episode "Blink of an Eye". His second wife, Gabrielle Beaumont (his first wife being the actress Irlin Hall with whom he has a daughter, the actress Kirstie Pooley (born 1954), directed that episode. Beaumont had previously directed Pooley in a 1978 edition of pre-school program Rainbow, in a 1978 episode of Shadows, in the 1984 TV movie Gone Are the Dayes (co-starring Bibi Besch), in a 1990 episode of TECX, in a 1992 episode of L.A. Law, in a 1996 episode of Dr. Quinn, Medicine Woman (starring Joe Lando), and the 1996 TV movie Beastmaster: The Eye of Braxus (co-starring Patrick Kilpatrick, Tony Todd, and David Warner). Pooley and Beaumont married in 1982 but have since separated.
Having played Professor Stahlman and his parallel Earth counterpart Director Stahlman in the Doctor Who serial "Inferno" in 1970, Pooley is one of the few actors to have appeared in both the Star Trek and the Doctor Who franchises.
Pooley has appeared in a number of British productions since the late 1940s, making his film debut in the 1948 mystery Penny and the Pownall Case. His subsequent credits include 1950's Highly Dangerous, 1952's This Woman's Angle (which also featured a young Joan Collins), and 1956's The Iron Petticoat. He also had roles in the BBC series Gravelhanger (1954) and Leave It to Todhunter (1958). His first American production was 1956's Anastasia, although this was filmed in Europe and his appearance went uncredited. In the 1960s, he made appearances on such popular British shows as The Four Just Men, Sherlock Holmes, The Troubleshooters, Dixon of Dock Green, and Paul Temple. His film credits during this time included 1966's Naked Evil (starring Lawrence Tierney) and 1969's The Assassination Bureau (with Clive Revill).
Pooley wrote and appeared in the 1970 horror film Crucible of Horror (aka The Corpse). He also wrote, directed, and co-starred in the 1971 comedy The Johnstown Monster. In addition, he continued making appearances on British series, including Doomwatch, Jason King, Special Branch, The Zoo Gang (starring Brian Keith), and the first episode of The Sandbaggers. And, in 1974, he co-starred with Patrick Stewart, as well as Tony Jay and John Rhys-Davies, in the acclaimed mini-series Fall of Eagles.
He went on to co-write the 1980 horror mystery The Godsend, which was directed by his wife, the aforementioned Gabrielle Beaumont. His other writing credits include the 1982 TV film Falcon's Gold and being an uncredited writer on the 1985 sci-fi film Lifeforce, which starred the aforementioned Patrick Stewart. Pooley's remaining acting credits include the 1985 TV movie Wallenberg: A Hero's Story, with Alice Krige, a role in the pilot episode of MacGyver and roles in Charlie Muffin, An Evening with Rosanne Seaborn and Fellini's Donut.
As of 2013, Pooley is the oldest known Star Trek actor still living.