This book deals with the 125 snake species known to inhabit Laos as of 2023. It is largely based on the literature, but also on the results of many field trips in Laos and long-lasting investigations of specimens deposited in numerous worldwide collections conducted by the three authors. As a result, a wealth of new and unpublished data are available for the snakes of this still poorly-known country. In contrast to many books mainly concentrating on pictures, each species and subspecies account includes the systematics, nomenclature, extensive discussion about the synonyms and the taxonomic history, detailed morphological descriptions, distribution, both general and within the borders of Laos, biology, legal protection, snakebites if necessary, and relevant bibliographical references.