Volume One in the Trilogy of Five
The Hitchhiker's Guide to the Galaxy
Douglas Adams
Volume Two in the Trilogy of Five
The Restaurant at the End of the Universe
Douglas Adams
Volume Three in the Trilogy of Five
Life, the Universe and Everything
Douglas Adams
Volume Four in the Trilogy of Five
So Long, and Thanks for All the Fish
Douglas Adams
Volume Five in the Trilogy of Five
Mostly Harmless
Douglas Adams