The term "Acoustic Microscopy" refers to the visualization of detail in the submillimeter to submicron range, by means of high frequency sound waves. Sound being a mechanical phenomenon, its use in microscopy reveals details of elastic structure related to stiffness, density, viscosity, etc. Because such information is not readily available from other techniques, acoustic microscopy complements the more conventional methods. In this review I will trace the historical development of acoustic microscopy from its beginning in the early '50s to the present time. I will discuss, in some detail, the technological evolution that led from the early instruments with millimeter resolution at megahertz frequencies to the present true microscopes that operate in the gigahertz region and achieve a resolution of microns.