The "Boundary-Scan Handbook" is a comprehensive technical book aimed at professionals in the electronics industry. The fourth edition provides detailed descriptions of the recent changes to the IEEE 1149.1 standard for test access ports and the boundary-scan architecture. This updated edition includes new chapters that address the impact of these changes on the work of test engineers, as well as information on the new standard 1149.8.1. The book is an essential resource for anyone looking to understand the fundamentals of the boundary-scan process and its practical industrial applications. It offers a clear and concise overview of the relevant standards and their implementation in practice.