Crop germplasmics is a scientific field dedicated to the study of diversity of crops and their wild relatives, as well as its utilization. It encompasses theories, technologies, and management systems involved in the formation, conservation, research, and utilization of crop diversity. This book introduces the theoretical and technical frameworks of crop germplasmics, providing a comprehensive overview of the discipline. The book begins with an Introduction that outlines the main themes, followed by a detailed exploration of fundamental theories. Subsequent chapters delve into specific theories, technical methods, and significant advancements within the workflow of germplasm. Topics covered include investigation and collection, safe conservation, phenotypic evaluation, genotyping and gene mining, germplasm enhancement, multi-omics research, big data construction, sharing and utilization, value assessment, property rights protection, and efficient management. The book emphasizes a seamless integration of academic rigor and accessibility, reflecting the cutting-edge and forward-looking nature of the discipline’s development. It serves as a valuable reference for professionals working with germplasm, as well as for postgraduate teaching, crop genetics and breeding, and basic research.