Robert Heinlein's Starship Troopers and Joe Haldeman's The Forever War are classic examples. Explores the fusion between man and machine, usually via the perfection of the Internet and virtual reality.
Writers are often research scientists themselves.
Sweeping in scope, epic fantasy usually concerns a battle for rulership of a country, empire or entire world, in a quintessential struggle between good and evil. Actual historical events are mixed with imaginary ones, bound together by magic. There is a significant crossover between the fantasy and romance genres. Mary Gentle , Anne McCaffrey's Acorna series , and Sheri S. Tepper 2001, HarperCollins Publishers.