The book consists of twenty five sections, exercises and two appendixes which may be divided per three main groups. The first sections are dedicated to the main laws of the multicomponent gas dynamics and primary knowledge from tensor analysis. The second group involved boundary value problem for Navier-Stokes equation, for multicomponent chemical nonequilibrium gas mixture and description of the method of matched asymptotic expansions which is one of perturbation theory methods. The third group is dedicated to the flow regimes of hypersonic viscid gas flow over blunt bodies with permeable surface. Considerable attention is paid to the solution of practical problems and exercises. This book is aimed for two purposes: as an effective classroom text which can be used by the lecturer, and which can be understood by students; as a handbook for engineers and scientists who have deal with hypersonic and/or high-temperature flow. Original manuscript is prepared as lecture notes for intensive courses on fluid mechanics given undergraduate and postgraduate students of applied mathematics and mechanics in Technion and Haifa University.