Definition

Science fiction is a fictional genre that contains elements which are currently considered impossible or unknown. Many of the themes incorporated in this genre are advanced technology, alternate universes and life on other planets. New ideas and technological advances are often explained in a very logical, if slightly vague manner.

I haven't had much experience with this genre. I am an avid fantasy reader and sometimes stories fall within or on the boundary of both genres. I love Douglas Adams and I also read a lot of anthologies which contain Sci Fi stories.