Elastic anisotropy is one of the most interesting forms of matter organization that has not received sufficient study yet. The elaboration of a simple method for the study of elastic anisotropy of solid media and in particular minerals and rocks is in large demand. In this book the fundamentals and practice of a new method acoustopolariscopy are given. The transducers for radiating and receiving longitudinal and shear waves, their developing and testing are depicted. Acoustopolariscopes of three modifications are described. The theory, elaborated devices and methods are necessary and sufficient to determine a full set of a solid anisotropic body's elasticity constants. Main attention is placed upon practical measurements of anisotropic media properties. The concluding sections are dedicated to the experimental study of elastic anisotropy of rock forming minerals and rocks from the Kola superdeep (12261 m depth) and Ural (6010 m depth) boreholes. The book can be useful for specialists investigating and testing anisotropic solid media, such as rocks, crystals, concrete, ceramics, plastic, metals, composite materials etc.