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.

Contents:
Preface to the fifth English Edition
Preface to the first American edition
Preface
Introduction
A note on the mathematical approach
1 The form
2 Forms taken out of the form
3 The conception of calculation
4 The primary arithmetic
5 A calculus taken out of the calculus
6 The primary algebra
7 Theorems of the second order
8 Re-uniting the two orders
9 Completeness
10 Independence
11 Equations of the second degree
12 Re-entry into the form
Notes
Appendix 1. Proofs of Sheffer's postulates
Appendix 2. The calculus interpreted for logic
Index of references
Index of forms
Appendix 3. Bertrand Russell and the Laws of Form
Introduction to Appendices 4 & 5
Appendix 4. An algebra for the natural numbers
Appendix 5. Two proofs of the four-colour map theorem
My simplest proof of the four-colour map theorem
Appendix 6. Last word
Appendix 7. The prime limit theorem
Appendix 8. Primes between squares
Appendix 9. A proof of Riemann's hypothesis via Denjoy's equivalent theorem
Closing remarks