Douglas Adams forever!
1. 
Don't Panic: The Official Hitchhiker's Guide to the Galaxy Companion
by:
Neil Gaiman
4.28 avg rating — 25,283 ratings 2. 
The Hitchhiker’s Guide to the Galaxy (The Hitchhiker's Guide to the Galaxy, #1)
by:
Douglas Adams
4.22 avg rating — 1,969,914 ratings 3. 
The Ultimate Hitchhiker’s Guide to the Galaxy (Hitchhiker's Guide to the Galaxy, #1-5)
by:
Douglas Adams
4.38 avg rating — 334,637 ratings 4. 
Last Chance to See: In the Footsteps of Douglas Adams
by:
Mark Carwardine
4.40 avg rating — 2,941 ratings 5. 
The Restaurant at the End of the Universe (The Hitchhiker's Guide to the Galaxy, #2)
by:
Douglas Adams
4.20 avg rating — 309,572 ratings 6. 
Life, the Universe and Everything (The Hitchhiker's Guide to the Galaxy, #3)
by:
Douglas Adams
4.16 avg rating — 246,190 ratings 7. 
Wish You Were Here: The Official Biography of Douglas Adams
by:
Nick Webb
4.14 avg rating — 2,895 ratings 8. 
Dirk Gently's Holistic Detective Agency (Dirk Gently, #1)
by:
Douglas Adams
3.97 avg rating — 146,635 ratings 9. 
Don't Panic: Douglas Adams & The Hitchhiker's Guide to the Galaxy
by:
Neil Gaiman
4.28 avg rating — 25,283 ratings 10. 
So Long, and Thanks for All the Fish (The Hitchhiker's Guide to the Galaxy, #4)
by:
Douglas Adams
4.09 avg rating — 182,136 ratings 11. 
Mostly Harmless (Hitchhiker's Guide to the Galaxy, #5)
by:
Douglas Adams
3.96 avg rating — 136,950 ratings 12. 
The Long Dark Tea-Time of the Soul (Dirk Gently, #2)
by:
Douglas Adams
4.04 avg rating — 88,593 ratings 13. 
Douglas Adams' The Hitchhiker's Guide to the Galaxy, Book 1 of 3 (The Hitchhiker's Guide to the Galaxy #1)
by:
John Carnell
4.55 avg rating — 2,228 ratings 14. 
Douglas Adams' the Hitchhiker's Guide to the Galaxy: The Authorized Collection
by:
John Carnell
4.49 avg rating — 874 ratings 
16. 
Young Zaphod Plays It Safe (Hitchhiker's Guide to the Galaxy, #0.5)
by:
Douglas Adams
3.67 avg rating — 29,557 ratings 17. 
Shada (Doctor Who) The Lost Adventure by Douglas Adams
by:
Gareth Roberts
4.22 avg rating — 6,200 ratings 18. 
The Salmon of Doubt: Hitchhiking the Galaxy One Last Time
by:
Douglas Adams
3.94 avg rating — 30,516 ratings 19. 
Hitchhiker's Guide To The Galaxy: The Filming of the Douglas Adams classic
by:
Robbie Stamp
4.41 avg rating — 3,048 ratings 
21. 
The Hitchhiker's Guide to the Galaxy: A Trilogy in Four Parts
by:
Douglas Adams
4.50 avg rating — 36,498 ratings 
24. 
Douglas Adams at the BBC: A Celebration of the Author's Life and Work
by:
Chris Emmett
4.10 avg rating — 83 ratings 
26. 
The Frood: The Authorised and Very Official History of Douglas Adams & The Hitchhiker's Guide to the Galaxy
by:
Jem Roberts
3.81 avg rating — 285 ratings 27. 
The Deeper Meaning of Liff: A Dictionary of Things There Aren't Any Words for Yet--But There Ought to Be
by:
Douglas Adams
3.94 avg rating — 4,794 ratings 