Holographic techniques are ideally suited for interferometric studies on dynamic systems and are especially valuable when adapted for use with a microscope. The holographic microscope and the method of hologram production is described as well as the basic methods for holographic interferometric microscopy (HIM).' HIM can produce interferograms in either one of two distinct ways. In the first way one obtains an interferogram of a subject by reconstruction from a doubly exposed hologram, where one of the two exposures acts as the reference wavefront. In the second way of producing an interferogram, one makes a simultaneous reconstruction from two separately recorded holograms. The use of HIM is illustrated by a description of two studies that deal with dynamic systems, one diffusion and the other a crystallization. One of the major advantages of HIM is found in the use of simple experimental technique and both studies used for illustration show that no complicated optics are required for either qualitative or quantitative data.