Who do you consider a Great Author of the last 50 years or so (first well-known work after 1970)? I'd like to get a feel for who's who in modern literature. Any language/culture. Fiction only.

Guy Gavriel Kay. First book published in 1984, part of a trilogy that was Tolkien-esque, quite decent, but not exactly ground-breaking. He's since gone on to something a little more unique, which he describes as "historical fiction with a quarter-turn to the fantastic." Impeccably researched but set an alternate world that's a close but not exact mirror of our own. This allows him to take a few small liberties with historical accuracy in service of telling a better story. Personally I think he really hit his stride in 1995 with The Lions of Al-Rassan, and almost everything he's written since then has been exceptional.