An intrinsic brittleness of oxide cuprates, the layered anisotropic structure and the supershort coherence length are the main features of HTS defining their properties. Taking into account these features, the researching of HTS microstructure and properties is presented, and also the possibilities of optimization of the preparation techniques and superconducting compositions are considered. The link 'composition-technique-experiment-theory-model' investigated in the book, assuming considerable HTSC defectiveness and structure heterogeneity, forms whole picture of modern representations on the microstructure, strength and connected with them the structure-sensitive properties of the materials considered. Especial attention is devoted in the book to the Bi-Sr-Ca-Cu-O and Y-Ba-Cu-O families, that today are most perspective for applications. The book includes great number of illustrations and references. The monograph is addressed to students, post-graduate students and specialists, taking part in the development, preparation and researching new materials.