The book "Theoretical Aspects of Transition Metal Catalysis" offers a comprehensive analysis of the theoretical foundations of transition metal catalysis, one of the most significant research areas in chemistry. Transition metals are crucial for a variety of chemical reactions, as they can significantly lower activation barriers. In recent years, research in this field has advanced, particularly through the use of modern quantum chemical methods that allow for the calculation of possible intermediates and transition states. These advancements have greatly improved the understanding of reaction mechanisms and revolutionized the search for new, more efficient catalysts. The book is divided into eight chapters and is authored by leading scientists in the field who summarize the developments of the past decade. It is aimed at professionals and students interested in the theoretical aspects of catalysis and those seeking a deep insight into the current state of quantum chemical research.