The Tertiary Phase is the third part of the radio series The Hitchhiker's Guide to the Galaxy, first broadcast in 2004.

As Douglas Adams had died in 2001, the third novel - Life, the Universe and Everything - was adapted for radio following instructions left by him. Dirk Maggs adapted, directed and co-produced the series, with John Langdon as the script editor.

There were also a number of cast changes, due to the deaths of several original cast members, most notably Peter Jones in 2000, who was replaced as the voice of The Book by his friend William Franklyn.

Story Summary[]

See individual Fits


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  • This phase was produced 23 years after the previous Secondary Phase.
  • The Tertiary Phase opens with Arthur and Ford on pre-historic Earth, and Trillian dismisses Zaphod's experiences at the Frogstar and the Total Perspective Vortex as a "psychotic episode", practically retconning most of the Secondary Phase. However, over the course of the Tertiary, Quandary and Quintessential Phases this is somewhat reconciled.