The five complete radio series included here are:

1. The Hitchhiker's Guide to the Galaxy: Primary Phase - Peter Jones is the book in the original full-cast BBC Radio 4 series - ''Fit the First to Fit the Sixth'' - which spawned a phenomenal hitchhiking legend.

2. The Hitchhiker's Guide to the Galaxy: Secondary Phase - Peter Jones is the book in the original full-cast BBC Radio 4 series - ''Fit the Seventh to Fit the Twelfth'' - which spawned a phenomenal hitchhiking legend.

3. The Hitchhiker's Guide to the Galaxy: Tertiary Phase - Don't panic! The Hitchhiker's saga continues with a brand new full-cast dramatization of ''Life, the Universe, and Everything'', the third book in the Douglas Adams' famous ''trilogy in five parts.''

4. The Hitchhiker's Guide to the Galaxy: Quandary Phase - Don't panic! The Hitchhiker's saga returns once again with a brand-new full-cast dramatization of ''So Long and Thanks for All the Fish'', the fourth book in Douglas Adams' famous ''trilogy in five parts.''

5. The Hitchhiker's Guide to the Galaxy: Quintessential Phase - Panic! It's the last ever installment of The Hitchhiker's Guide to the Galaxy, with a brand new full-cast dramatization of ''Mostly Harmless'', the final book in Douglas Adams' famous ''trilogy in five parts.''