Where were you last Pluterday? is a serio-comic science fiction novel by Paul van Herck, originally released in Dutch in 1968 as Sam, of de Pluterdag by J.M. Meulenhoff (in their science fiction and fantasy range M=SF as the 14th book of the range) and released in English by DAW books in 1973. The novel won the first prize at the European Science Fiction Convention (EuroCon) in Trieste, Italy. Source: Wikipedia (en)