This book describes the significance of amino acids and their derivatives in plant stress adaptation/tolerance, and presents biotechnological strategies for the manipulation of amino acids and their major derivatives to improve abiotic and abiotic stress tolerance in crop plants. Chapter 1 presents a general introduction on the role of amino acids and their derivatives in plant stress response. The succeeding chapters focus on amino acids and peptides (chapters 2-6), and amines and brassinosteroids (chapters 7-16), and their role in plant stress adaptation. A brief discussion of the prospects for further research (chapter 17) is included. This publication is suitable for scholars and researchers exploring sustainable strategies for crop improvement and abiotic stress tolerance.