Ray Bradbury is a science fiction author, and one of the greats in the field. He has written science fiction for well over 60 years, and his novels are timeless. But his writing isn't just limited to novels; he also does short stories, poems, and has made movies as well.
The book that he's probably most well known for is Fahrenheit 451, and it is something that anyone would be proud to be known for. It's a fantastic book with a moving message about the world and censorship; ironically, this book was, itself, censored.
His book of short stories about Mars, The Martian Chronicles, is excellent as well. As are his other books, but if you're looking for a place to start in reading some of Bradbury's books, those would be two good suggestions. If you want something not so heavy on the sci-fi and more in the scary area, try Something Wicked This Way Comes.