They're kind of hard to come by in the brick-and-mortars, so you might want to try Amazon. Even there, they're a little pricey. You probably should start in order, but book 3 is generally considered the point where the books hit their stride. If you've seen the movie and loved the interplay between Remo and Chiun, that's the book where it came into focus.
Thanks for the info!
I live in a small college town and our Citizens Library has always found any book I've ever asked for so I'll try them before Amazon.