The Hitchhiker's Guide to the Galaxy radio series is a "Trilogy in six parts". Comprising:

Original CreationEdit

The series was originally written as a radio serial (rather than being adapted from a book), and was conceived and realised by Douglas Adams. What is now known as the Primary Phase was the first part to be recorded in 1978.

Primary and Secondary PhasesEdit

see also individual article pages

These two phases are generally grouped together as these were recorded and produced while Douglas Adams was alive, from 1978 to 1980.

Tertiary, Quandary and Quintessential PhasesEdit

see also individual article pages

These were produced onward from 2003, 23 years after the production of the secondary phase (and 2 years subsequent to Douglas Adams' own death).

Hexagonal PhaseEdit

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This was produced in 2018.

Boxed set top
Boxed set back

Complete boxed set released by the BBC.