Laws of Form by G Spencer-Brown 5th English edition: At last this all-time classic has been reset, allowing more detailed explanations and fresh insight. There are seven appendices, doubling the size of the original book. Most exiting of all is the first ever proof of the famous Riemann hypothesis. To have, in print, under your hands and before your own eyes, what defied the best minds for a century and a half, is an experience not to be denied.