Originally Posted by HarryT
If you want to find some great authors who are most definitely still actively writing, you can do no better than to head over to Baen and check of some of the books in their free library.
Actually I think that is bad advice. If you like a certain kind of sf you will find it on Baen. But if you like challenging sf or like to read about interesting ideas this is the wrong place to look.
Here are some links: