Some of the busiest people in show business don’t exist:

• The name George Spelvin is traditionally used in American theater programs when an actor’s name would otherwise appear twice.
• In the London theater, Walter Plinge gets the credit when a part has not been cast.
• On BBC television dramas in the 1970s, David Agnew was credited when contractual reasons prevented a writer’s name from being used.
• When a Hollywood director no longer wants credit for a film, the name Alan Smithee is used.

That last one is such an open secret — “Smithee” even directed a Whitney Houston video — that the Directors Guild finally abandoned it in favor of random pseudonyms, starting with the 2000 James Spader bomb Supernova, directed by “Thomas Lee” (Walter Hill).