Geophysics uses many of the methods and techniques of physics to study the solid earth and planets. Experimental techniques in modern geophysics naturally fall into two categories: field and laboratory. Field experiments are designed to collect basic data on the structure of earth and planetary interiors, the dynamic processes by which these bodies evolve, and the nature and source of any planetary field. Laboratory experiments are designed to aid the interpretation of the basic field data, and to make inferences when no primary data are available. We have followed this division in organizing the two volumes in this set. Volume 24, Part A discusses the laboratory techniques, and Volume 24, Part В discusses the field techniques used in geophysics.