Annals of the International Geophysical Year, Part IV: Geomagnetism covers the principles and methods of observation of geomagnetism. This book is organized into four parts encompassing 17 chapters that also consider the concept of seismology and cosmic radiation. The first two parts focus on geomagnetism, its general principles, technique of scaling, method of measurement, and equipment for recording. These parts also provide results of geomagnetic activity obtained the Earth-current installation at the U.S.S.R. stations. The third part presents the monthly bulletins containing the reduced data on seismological activity during the International Geophysical Year. This part also deals with the use of seismological codes for data transmission from seismograms. The fourth part describes the instrumentation for measuring cosmic-ray intensity changes and the design specifications for a meson intensity recorder. This book is directed toward to geophysicists.