Dr. Evans' lecture has been an excellent introduction to my presentation. I would like to say, however, that at one time we were asked if we were for or against evaluation by acoustic emission, and we said that we were against it. The reason we were against it was because of a doubt that some of the test procedures were actually telling us anything about cracking. We, therefore, accepted as a chore to try to do what Dr. Evans said should be done, that is, see if we can discriminate between slip, twinning, fracture in acoustic emission signals.