The hitchhiker's guide to the galaxy
Douglas Adams
HHGTTG - The Lost Chapters
Dirk Gently's Holistic Detective Agency
Life, the Universe and Everything
The long dark tea-time of the soul
Mostly harmless
Last Chance to See
Young Zaphod Plays It Safe
So Long, and Thanks for All the Fish
The Restaurant at the end of the universe
The Ultimate Hitchhiker's Guide - All Six Books
The Salmon of Doubt