Back at Livermore we continued to look at a variety of problems: how nuclear explosives can be made more effective by making more kinds of them. And at first our only real success was to get people like Harold Brown, Johnny Foster, John Nuckolls more and more interested in the various things that we could do and at the beginning we produced remarp- remarkable record of lack of success. Our first attempt was to go ahead with one of my favorite ideas, still not realized, but I believe of considerable importance: making very small nuclear explosions, essentially by using slower neutrons and much less material. Well in a way we succeeded only too well. The first test we made, a shot in Nevada, I remember our watching it. The shot went off all right but it was immediately clear that there was something a little unexpected. The shot was fired on top of a tower and after we fired it, the bottom of the tower was still standing. We found out that the properties of the material with which we were working were well known at high neutron energies, at low neutron energies, but not at in- intermediate nuclear energies, which was the source of our trouble.