In the twenty-five years since the first edition of 'Ultrasonic Flaw Detection for Technicians' was published, there have been a number of advances in transducer technology and the flaw detection instruments. The gradual acceptance by the industry that the sizing of weld defects by intensity drop was not as accurate as had been claimed led to the development of the TOFD technique. Modern digital flaw detectors and computer technology allow far more information to be store by the operator. I felt that it was time to give the book a thorough review and to try to address some of the advances in this second edition.