The standard work on proof marks is now available in a fully revised and updated edition. The background for the proof system has always been the improvement of weapon quality. These quality controls had a significant impact on the sales success of individual manufacturers, leading to more and more countries implementing state examinations. To mutually recognize the proofs, international law was established through proof conventions in 1914 and 1924. The national proof marks retained their validity, resulting in an extensive set of regulations from which the manufacturing period can often be determined. Today, most European countries are united in the CIP as an international association, with the latest uniform CIP marks already included in this book.