5 books in series

Hitchhiker's Guide BBC Radio Series

Hitchhiker's Guide BBC Radio Series is a 5-book series with 5 primary works first released in 1978 with contributions by Douglas Adams and Eoin Colfer.

The Hitchhiker's Guide to the Galaxy: Primary Phase
The Hitchhiker's Guide to the Galaxy: The Secondary Phase
The Hitchhiker's Guide to the Galaxy: Tertiary Phase
The Hitchhiker's Guide to the Galaxy: Quandary Phase
The Hitchhiker’s Guide to the Galaxy: Hexagonal Phase: And Another Thing...