Its title is the message left by the dolphins when they departed Planet Earth just before it was demolished to make way for a hyperspace bypass, as described in The Hitchhiker's Guide to the Galaxy.

Russell explains that Fenny, who is sitting in a drugged state in the back seat of the car, became delusional after worldwide mass hysteria, in which everyone hallucinated "big yellow spaceships" (the Vogon destructor ships that "demolished" the Earth).

He discovers her home by accident when he searches for the cave in which he had lived on prehistoric Earth; Fenchurch's flat is built on the same spot.

Arthur and Fenchurch travel to California to see John Watson, an enigmatic scientist who claims to know why the dolphins disappeared.

Watson has abandoned his original name in favour of "Wonko the Sane", because he believes that the rest of the world's population has gone mad.

The bowl explains audibly that the dolphins, aware of the planet's coming destruction, left Earth for an alternate dimension.

Due to previous events, Marvin is now approximately 37 times older than the known age of the universe and is barely functional.

The different tone also reflects the rushed nature of the writing; Adams's editor Sonny Mehta moved in with him to ensure that the book met its deadline, which had been repeatedly extended.

As a result, Adams later stated that he was not entirely happy with the book, which includes several jarring authorial intrusions, which his biographer Neil Gaiman described as "patronising and unfair".

[2] In 1993, Library Journal said that So Long, and Thanks for all the Fish was "filled with loopy humor and pretzel logic that makes Adams' writing so delightful".

[4] Dave Langford reviewed So Long, and Thanks for All the Fish for White Dwarf #62, and stated that "Sequelholism has drained Adams of his high-speed inventiveness which made him famous.

[citation needed] The Quandary Phase of the radio series is drawn from So Long and Thanks for All the Fish, but is not a direct audiobook reading.