This book, *Topological Indices and Related Descriptors in QSAR and QSPR* edited by James Devillers and Alexandru T. Balaban, provides a comprehensive overview of the theory and applications of molecular descriptors in quantitative structure-activity relationships (QSAR) and quantitative structure-property relationships (QSPR). The editors, both renowned contributors to the field, have assembled a diverse group of international authors to cover various aspects of molecular descriptors. The book is divided into 17 chapters, each focusing on different aspects of topological indices and related descriptors. Key topics include the historical development of topological indices, graph theory, vertex- and edge-weighted molecular graphs, distance matrices, detour indices, molecular connectivity indices, complexity indices, and their applications in QSAR and QSPR modeling. The book also discusses novel strategies for deriving topological indices, information-theoretic indices, autocorrelation methods, and neural network models. The contributions highlight the work of Croatian scientists, who have made significant contributions to the field, particularly in the development of the Zagreb group indices. The book is a valuable resource for researchers and students in chemistry, biochemistry, biology, toxicology, medicinal chemistry, drug design, engineering, pharmaceuticals, and environmental sciences, as well as for educators in teaching modeling techniques.This book, *Topological Indices and Related Descriptors in QSAR and QSPR* edited by James Devillers and Alexandru T. Balaban, provides a comprehensive overview of the theory and applications of molecular descriptors in quantitative structure-activity relationships (QSAR) and quantitative structure-property relationships (QSPR). The editors, both renowned contributors to the field, have assembled a diverse group of international authors to cover various aspects of molecular descriptors. The book is divided into 17 chapters, each focusing on different aspects of topological indices and related descriptors. Key topics include the historical development of topological indices, graph theory, vertex- and edge-weighted molecular graphs, distance matrices, detour indices, molecular connectivity indices, complexity indices, and their applications in QSAR and QSPR modeling. The book also discusses novel strategies for deriving topological indices, information-theoretic indices, autocorrelation methods, and neural network models. The contributions highlight the work of Croatian scientists, who have made significant contributions to the field, particularly in the development of the Zagreb group indices. The book is a valuable resource for researchers and students in chemistry, biochemistry, biology, toxicology, medicinal chemistry, drug design, engineering, pharmaceuticals, and environmental sciences, as well as for educators in teaching modeling techniques.