Acoustic microscopy enables you to image and measure the elastic properties of materials with the resolution of a good microscope. By using frequencies in the microwave range, it is possible to make the acoustic wavelength comparable with the wavelength of light, and hence to achieve a resolution comparable with an optical microscope. The contrast gives information about the elastic properties and structure of the sample. Since acoustic waves can propagate in materials, acoustic microscopy can be used for interior imaging, with high sensitivity to defects such as delaminations. Solids can support both longitudinal and transverse acoustic waves. At surfaces a combination of the two known as Rayleigh waves can propagate, and in many circumstances these dominate the contrast in acoustic microscopy. Contrast theory accounts for the variation of signal with defocus, V(z). Acoustic microscopy can image and measure properties such as anisotropy and features such as surface boundaries and cracks. A scanning probe microscope can be used to detect ultrasonic vibration of a surface with resolution in the nanometre range, thus beating the diffraction limit by operating in the extreme near-field. This 2nd edition of Acoustic Microscopy has a major new chapter on the technique and applications of acoustically exited probe microscopy.