Work in rock magnetism during the last 4 years in the United States has been concentrated on several important intrinsic problems, the solutions of which are needed to answer some of the larger questions now being raised in paleomagnetism. The questions include whether it is feasible to measure variations in geomagnetic field intensity in rocks as old as Precambrian, what the exact frequency of geomagnetic reversals throughout the earth's history is, and whether the natural remanence of rocks is thermal or chemical in origin and, if it is chemical, when during the rocks' history it was acquired. A summary of some of this research is contained in the following paragraphs. Additional references to significant research in rock magnetism and related instrumentation are contained in the bibliography.