A second edition, retitled Don't Panic: Douglas Adams & The Hitch Hiker's Guide to the Galaxy was published in the UK in July 1993, containing additional material by David K. Dickson (ISBN 1-85286-411-7).
A third edition, with another slight title revision (now known as Don't Panic: Douglas Adams & The Hitchhiker's Guide to the Galaxy) was published in the UK in June 2002, and contains further additional material, this time by M. J. Simpson (ISBN 1-84023-501-2).
The updated North American edition was published by Titan Books in October 2003 (ISBN 1-84023-742-2).