I think, by definition, science fiction assumes some technology that we don't have (not realistic?). P.K. Dick was famous for writing novels that included only

I think, by definition, science fiction assumes some technology that we don't have (not realistic?). P.K. Dick was famous for writing novels that included only one small leap in technology and showing how people would respond to them. His book, "The World Jones Made" doesn't include any particular high tech but is terrific nonetheless. Isaac Asimov tried to do this, too. "Foundation" comes to mind as a book that seems entirely realistic.