I've read this book in paper form. It is my favorite book, however it is now falling apart so badly that I am afraid to read it again. I was very glad to find it in ebook form. If you like this story, there is a sequel, "Space Barbarians" but it is not as good. Also Robert A. Heinlein wrote a story with a similar, underlying theme called "The Moon Is a Harsh Mistriss". The character of his book is very different however.