So Long, and Thanks for All the Fish (Hitchhiker’s Guide #4)

Alternate cover editions for this ISBN can be found here and here. From The Hitch Hiker's Guide to the Galaxy: "...and then, one Thursday, nearly 2,000 years after one man had been nailed to a tree for saying how great it would be to be nice to people for a change, a girl sitting on her own somewhare in Rickmansworth suddenly realised what it was that had been going wrong all this time, and she…