The relationship between fiction and scientific writing (from historiography to hard science) is explored, with special emphasis on the historical novel and on science fiction. Speaking of the past (or of the future) is almost always a different way of approaching the problems of the present, exploiting the freedom offered by the estrangement effect and by the lack of ‘scientific rigour’. A number of significant examples are discussed, ranging from 17th century historical novels to 21st century science fiction. It is however worth taking into account that also the “scientific” writing has a literary nature, and the distance between the two approaches is not necessarily abysmal.