The Comment Tater

I've got hooked on reading Orson Scott Card's Ender's Game series. I have read Ender's Game, Ender's Shadow, Xenocide, Children of the Mind and am now reading Shadow of the Hegemon. there are a few other books in the series but I think I'm ready to venture on to new frontiers.

Xenocide and Children of the Mind were intriguing to me because they introduced the concept of faster than light travel in ways I hadn't thought about before. I'm looking now to read books by other authors that can give me the same wow feeling. I want to be wrapped up in the story and learn or expand my mind at the same time. I'm keenly interested in physics. Any suggestions? Here are a couple books that I was considering.