Who is Mr. X?

Cast

• 

  Bob Newhart

  Robert Hartley

• 

  Suzanne Pleshette

  Emily Hartley

• 

  Bill Daily

  Howard Borden

• 

  Marcia Wallace

  Carol Kester

• 

  Peter Bonerz

  Jerry Robinson

• 

  John Fiedler

  Mr. Emil Peterson

• 

  Jack Riley

  Elliot Carlin

• 

  Alan Manson

  Congressman Avery

• 

  Jennifer Warren

  Ruth Corley

• Claudette Duffy

  Sister Mary Catherine

• 

  Howard Hesseman

  Augie (voice) (uncredited)