This book is centered around the major issues relating to criminal law in Thailand and aims to offer a detailed and systematic overview of the Thai criminal justice system. It is designed as a traditional textbook of criminal law which provides a succinct focused coverage of all the relevant aspects of laws, judgments, and legal reforms in a concise and readable form. Although all topics have been previously treated in the Thai language, this is the first and most comprehensive work in the English language about Thai criminal law. The book covers not only the legal system, starting from the Penal Code of 1908 and emphasizing the substantial changes that have been introduced in the past decades, but also the deep influence of doctrine and case law. It is built up in several layers, starting from the general rule, to gradually examine the more specific ones. The book begins with the elementary legal concepts to be learned by the reader, by defining the fundamental principles underlying the Thai criminal system and outlining its objectives. It then extensively describes the main offences under the Thai Penal Code and classifies those breaches of law which are crimes from those which are merely illegal without being criminal.