Graphene Quantum Dots have been the subject of significant research interest, and numerous studies have been devoted to them, both theoretical and experimental, from purely academic and practical application points of view. This book makes its own valuable contribution to this area of knowledge and technology, covering various facets of research and applications of GQDs. Chapter one considers the aspects of synthesis and characterization of graphene quantum dots. Chapter two is devoted to the use of GQDs for detection of different analytes, from inorganic ions via biomolecules to pathogenic microorganisms. Chapter three considers in detail the role of graphene quantum dots in different biological and energy-related applications. Chapter four reviews the recent progress in the research of graphene quantum dots for energy applications and storage devices. Chapter five covers the aspects of using graphene quantum dots as promising catalysts for electrocatalytic water splitting. Chapter six considers the uses of GQDs for various biological and biomedical applications. Finally, Chapter seven covers different aspects of investigation and applications of GQDs. This book will be highly attractive for the broad audience of students and researchers interested in the ever-developing area of the graphene quantum dots, providing them with the useful knowledge of various characteristics of GQDs and peculiarities of their synthesis and characterization. Moreover, it will provide readers with a review of the history of GQD investigations, the current state of the art of their research and different applications, and perspectives in this field of science and technology.