Originally built as one of many failed prototypes of Sirius Cybernetics Corporation's GPP (Genuine People Personalities) technology, Marvin is afflicted with severe depression and boredom, in part because he has a "brain the size of a planet"[1] which he is seldom, if ever, given the chance to use.

When kidnapped by the bellicose Krikkit robots and tied to the interfaces of their intelligent war computer, Marvin simultaneously manages to plan the entire planet's military strategy, solve "all of the major mathematical, physical, chemical, biological, sociological, philosophical, etymological, meteorological and psychological problems of the Universe, except his own, three times over", and compose several lullabies.

It was changed to "Marvin" partly to avoid causing offence, but also because it was pointed out to Adams that on radio the name would sound like "Martial", which would have undesirable military connotations.)

According to his autobiography read in the Secondary Phase of the radio series, Marvin was constructed, much against his own wishes, by the Sirius Cybernetics Corporation to prototype human personality artificial intelligence.

I have a horrible feeling it's still there...The cutaway illustration of Marvin made by Kevin J. Davies for the "Depreciation Society" featured a "rat cavity".

[4] As the menial labourer on the Heart of Gold spaceship, he grew immensely resentful of the insistence of his new masters (Zaphod Beeblebrox and Trillian; later also Ford Prefect and Arthur Dent) that he open doors, check airlocks and pick up pieces of paper.

During an apparently suicidal confrontation with a pair of trigger-happy cops, the crew are teleported directly from Magrathea into the future to the Restaurant at the End of the Universe to find that, in fact, they have not travelled at all.

[citation needed] Deciding they had better leave, the crew make a desperate and futile attempt to engage Marvin's enthusiasm (he "hasn't got one") before he simply does what they really want and opens the door to the ship they want to steal.

The ship turns out to be a Haggunenon battle cruiser, and the entire group, including Marvin, but excluding Ford Prefect and Arthur Dent, who escape, are eaten by its crew.

Marvin's subsequent survival is never explained, but against all probability, he eventually finds himself on Ursa Minor Beta, just in time to rescue Zaphod from a robotic tank.

Marvin rejoins the crew on the Heart of Gold, and using the improbability drive programmed by Zaphod Beeblebrox the Fourth, takes them to the ravaged planet Brontitall.

Having landed in a giant floating marble copy of a plastic cup, the crew accidentally find themselves falling several miles through the air.

[citation needed] However, in the Tertiary Phase, Trillian claims this story is Zaphod's hallucination, especially as the reverse temporal engineering explanation has not entered the plot yet.

[citation needed] A difference between the radio and TV series occurs in the novels when the Heart of Gold crew arrive on the ancient planet of Magrathea.

[citation needed] In the third novel, Life, the Universe and Everything, we find that Marvin survived his collision with the sun of Kakrafoon, and was sent back in time by the Improbability Field projected by the Heart of Gold to be rescued by a scrap metal merchant on Sqornshellous Zeta.

The merchant grafted a steel rod to Marvin's now-lost leg and sold him to a Mind Zoo, where excited onlookers would try to make him happy.

Marvin was left in the swamp, his false leg having trapped him in the mud, so he spent just over 1.5 million years walking around in a circle, "just to make the point."

The once formidable Krikkit robots find themselves overcome with crippling sorrow and depression, and rather than focusing on their mission of extermination, instead sulk in corners doing quadratic equations.

"[citation needed]) However, in the 2005 radio adaptation of the fifth novel in the series, Mostly Harmless, in which Marvin did not originally appear, he has a cameo at the end of the last episode alive and well.

[citation needed] Stephen Moore released two pop singles—"Marvin/Metal Man"[5] and "Reasons to Be Miserable/Marvin I Love You" (double B-side)—in the UK in 1981, though neither reached the top 40.

The song involves a spoken exchange between the starship captain (also played by Moore, as is a cameo radio voice) and the depressed robot Marvin.

[9] "How I Hate the Night", also known as "Marvin's lullaby", was published in the book Life, the Universe and Everything, where it is described as "a short dolorous ditty of no tone, or indeed tune."

The first verse of "Marvin's Lullaby" appears close to the end of the episode "Fit the Seventeenth", and the second verse soon after the start of "Fit the Eighteenth" as listed below:[citation needed] The line "try to count electric sheep" is a reference to Philip K. Dick's novel Do Androids Dream of Electric Sheep?, which inspired the movie Blade Runner.

[citation needed] British alternative rock group Radiohead named "Paranoid Android", the lead single from their 1997 album OK Computer, after Marvin.

"[11][12] Marvin's origins (including those of the Sirius Cybernetics Corporation, and the HitchHikers handheld device) are referenced in the 2008 radio series The Long Dark Tea-Time of the Soul.