The Hitchhiker's Trilogy

From Author Wars - https://authorwars.com/publications/the-hitchhikers-trilogy-171611.html

Overview:

Title: The Hitchhiker's Trilogy
Author: Douglas Adams
Year: 1984
ISBN-10: 0517552000
Publisher: Harmony Books
Price: $15.95
Pages: xi+468
Binding: Hardcover
Type: Omnibus
Title Reference: The Restaurant at the End of the Universe
Notes: Page count from Reginald3 and Worldcat, who both date this publication in 1983. Locus1 mentions February 1984. Amazon.com mentions 1984-01-05. Contents' page numbers from 6th printing copy on Archive.org.