The book is devoted to the problem of microgeometry properties and anisotropy relations in modern piezo-active composites. These materials are characterized by various electromechanical properties and remarkable abilities to convert mechanical energy into electric energy and vice versa. Advantages of the performance of the composites are discussed in the context of the orientation effects, first studied by the authors for main connectivity patterns and with due regard to a large anisotropy of effective piezoelectric coefficients and electromechanical coupling factors. The novelty of the book consists in the systematization results of orientation effects, the anisotropy of piezoelectric properties and their role in forming considerable hydrostatic piezoelectric coefficients, electromechanical coupling factors and other parameters in the composites based on either ferroelectric ceramic or relaxor-ferroelectric single crystals.