Ultraheavy cosmic‐ray nuclei, those with atomic number over thirty, constitute less than about one in107of the relativistic particles that stream through our solar system, yet they promise to lead to a major contribution in our understanding of the complex phenomena of the cosmic‐ray gas that pervades interstellar space. The study of these nuclei should advance our understanding of the sources of cosmic rays as well as of the nature of the physical processes that influence the particles after their acceleration. This work is greatly accelerating with the advent of satellite experiments, such as the Skylab mission pictured in figure 1.