Marvin is the ship's robot aboard the starship Heart of Gold. Severely depressed, Marvin was built as a prototype of Sirius Cybernetics Corporation's "Genuine People Personalities" technology. He has a brain the size of a planet, but seldom gets the chance to use it. Instead, he continually whines about his troubles, irritating his crewmembers.
Marvin's voice was performed by Stephen Moore on radio and television; David Learner operated his body on television. He is "probably... the most popular character to appear in the Guide," according to Geoffrey Perkins, producer of the radio series. He released two pop singles - "Marvin" / "Metal Man" and "Reasons to be Miserable" / "Marvin I Love You" (double B-side) - in the UK in 1981, though neither reached the top 40.
According to Douglas Adams, "Marvin came from Andrew Marshall. He's another comedy writer, and he's exactly like that." Indeed, in an early draft of Hitchhiker's, the robot was called Marshall. However, Adams also admitted that Marvin is part of a long line of literary depressives, such as A.A. Milne's Eeyore or Jacques in Shakespeare's As You Like It, and even owes something to Adams's own periods of depression.