The scanning acoustic microscope operating in water with a frequency of 2.5 GHz (wavelength 6000 Å) has been used to nondestructively characterize materials and devices in a manner inaccessible to optical and electron microscopy. Adhesion of thin films of Cr on glass (optical masks for photolithography) is shown to be a strong source of acoustic microscope contrast. This offers nondestructive evaluation of film adhesion on a microscopic scale for the first time. Study of intentionally damaged integrated circuit structures reveals damage features not visible in optical microscopy. Microscopic subsurface imaging of composite structures is presented, as in other recent acoustic microscope imaging of materials. Recent theoretical work in acoustic response of layered materials is reviewed.