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