Any chess enthusiast knows how important tactics is in the ''royal game'' and how crucial it is to make a. thorough study of this aspect of the game. But up to now opinion has been divided on the best way of studying tactics. The well-known Soviet international, grandmaster and chess author Averbakh has developed an entirely novel approach, which is expounded in the present work. His main aim was to create a theoretical basis with whose aid the learner can effortlessly study the numerous and manifold tactical problems facing the chess player. Averbakh begins by examining the simplest situations resulting from confrontations between different pieces. He then proceeds to analyze more complex situations and demonstrates the importance of the double attack. With instructive examples he proves that double attacks in the broadest sense are the basis of most tactical operations. This discovery prompted Averbakh to focus his attention on the double attack in the first part of the book. The second part is devoted to combinations. The author delves into the question of what lies hidden behind the mysterious concept of harmony of pieces. The astonishing simplicity of the answer he finds to this question enables him to reduce the bulk of the combinations to a handful of basic elements. From this Averbakh derives a convincing definition of the term ''combination'' and introduces a new, promising system of classifying different combinations. All this is explained with the aid of numerous practical examples including complete games and chess problems. The book contains special chapters with numerous exercise problems for the reader to test and consolidate his newly-acquired skill. In this way Averbakh's work is both very instructive and easy to understand.