In 1986, after three years of additional research progress, the international community devoted to the generation and application of ultrahigh magnetic fields and currents, it reconvened at Santa Fe, New Mexico. The Conference had been announced at the previous meeting (Megagauss III) held at Novosibirsk, USSR, in 1983 under the auspices of the Lavrentyev Institute of Hydrodynamics and the Siberian Branch of the Soviet Academy of Sciences. The present meeting (Megagauss IIII) was hosted by Los Alamos National Laboratory (LANL) with active assistance by scientists from Lawrence Livermore National Laboratory (LLNL), the Air Force Weapons Laboratory (AFWL) and Sandia National Laboratories, Albuquerque, NM (SNLA). Over 220 scientists and engineers from eight countries (including, for the first time, the People's Republic of China) participated in the technical sessions of the Conference, which included more than one hundred papers, and in the subsequent tours of local laboratories (LANL, SNLA, AFWL).