The Hitchhiker's Guide to the Galaxy first aired on BBC Radio 4 in 1978. Its opening episode, “Fit the First,” was broadcast on 8 March 1978, beginning Douglas Adams's influential science-fiction comedy series.
The original radio run consisted of six episodes, later known as the Primary Phase. It introduced Arthur Dent, Ford Prefect, Zaphod Beeblebrox, Trillian, Marvin the Paranoid Android and the Guide itself. The story begins when Earth is demolished to make way for a hyperspace bypass.
The series was unusually ambitious for radio. It was the BBC's first comedy programme produced in stereo, using experimental music and elaborate sound effects from the BBC Radiophonic Workshop. The programme's success led to repeats, an LP adaptation, novels and later television and film versions.
A common mix-up is 1979, the year the first Hitchhiker's novel was published. The second radio series aired in 1980, while later radio phases appeared in 2004, 2005 and 2018.