This is, perhaps, Heinlein at his best. The first 50 pp or so are a little slow, but it picks up after that. As the main character shifts from reality to reality, Heinlein embarks on the moral, a person must have faith. Faith in a specific deity or religion is not important, faith in something more than ourselves is all that matters. While it is a somewhat simple message, the amazing tale that Heinlein weaves and the excellent characters he creates make this novel more than worth the read. This is a must-read.