Life, the Universe and Everything (Hitchhiker's Guide to the Galaxy Book 3)
So Long, and Thanks for All the Fish (Hitchhiker's Guide to the Galaxy Book 4)
Mostly Harmless (Hitchhiker's Guide to the Galaxy Book 5)
The Hitchhiker's Guide to the Galaxy
And Another Thing... (Hitchhiker's Guide to the Galaxy Book 6)
The Salmon of Doubt: Hitchhiking the Galaxy One Last Time (Dirk Gently Book 3)
Long Dark Tea-Time of the Soul (Dirk Gently Book 2)
Dirk Gently's Holistic Detective Agency Box Set: Dirk Gently's Holistic Detective Agency and The Long Dark Tea-Time of the Soul
Dirk Gently's Holistic Detective Agency