This is the first volume of a first-of-its-kind four-volume book set that provides readers with up-to-date information on α-amino acids, the potential challenges in working with α-amino acids, the protecting groups for the carboxyl, amino and side chain groups of the amino acids, and the most popular heterocyclic compounds that are originating from α-amino acids. These heterocyclic compounds include hydantoins, thiohydantoins (including 2-thiohydantoins, 4-thiohydantoins, 2,4-dithiohydantoins), 2,5-diketopiperazines, N-carboxyanhydrides, N-thiocarboxyanhydrides, sydnones, sydnonimines, azlactones, pseudoazlactones, and oxazolidin-5-ones. This is the first resource to comprehensively collect all the heterocycles that can be directly prepared from α-amino acids. In addition, almost all kinds of synthetic methods for a particular type of heterocycles from α-amino acids are included, along with the detailed mechanistic discussions and experimental procedures. Volume 1: Protecting Groups collects and discusses the 260 protecting groups relating to amino acids, which have been organized by carboxyl group, amino group, and side chain group. The conditions to introduce these protecting groups as well as their deprotecting procedures have also been incorporated, along with the physical properties, solvent effects, and temperature effects on the solubility of amino acids. It presents the solubility of glycine and phenylalanine in a variety of solvent systems to show the impact on amino acid, where glycine generally represents the polar amino acid whereas phenylalanine represents the amino acid of non-polar side chain. The other volumes include: Volume 2: Hydantoins, Thiohydantoins, and 2,5-Diketopiperazines Volume 3: N-Carboxyanhydrides, N-Thiocarboxyanhydrides, and Sydnones Volume 4: Azlactones and Oxazolidin-5-ones All together, this unique 4-volume set thoroughly covers the two types of heterocyclic compounds that are originated from alpha-amino acids, providing carefully compiled updated information with detailed examples. The author has shared many thoughtful insights based on his strong background in physical organic chemistry. The volumes will be highly valuable for graduate students and senior students, as well as for professors and researchers working in the field of medicinal and pharmaceutical chemistry, organic chemistry, organic synthesis, heterocycles, and proteins and peptides.