Mostly Harmless
Appearance
Mostly Harmless is a novel by Douglas Adams, the fifth book of the Hitchhiker's Guide to the Galaxy series.
Being the fifth book in a trilogy it wasn't clear that this was the concluding book in the series until Douglas Adams's death on May 11, 2001.
"Mostly harmless" are the only two words that appear under the "Earth" entry in the Hitchhiker's Guide to the Galaxy (the encyclopedia mentioned in the novel, not the novel written by Douglas Adams).