The history of the Galaxy has got a little muddled, for a number of reasons: partly because those who are trying to keep track of it have got a little muddled, but also because some very muddling things have been happening anyway.

He put on a little light music instead.

"Mostly Harmless" is the title of fifth in a series of novels (as well as the fifth in a series of radio dramas). The five works in the series are generally referred to as "The Hitchhiker's Guide to the Galaxy", as is the series of radio dramas. Though there are unabridged audio recordings of these works, the radio dramas are considerably different from the printed works.