This textbook clarifies synchronization issues in telecommunications in an easy-to-follow way, focusing less on theory and more on practical aspects. The book is intended for a wide range of readers interested in the basic synchronization concepts in their wide application for development, maintenance, and conformity assessment of telecommunications equipment and networks. The authors show how, though synchronization in telecommunications has experienced rapid development, the foundational theory and the basic definitions, mathematical tools, and well-developed “classical” technologies have remained. The authors have studied the ITU-T, ETSI, IEEE standards, and extracted practical topics of synchronization. The collection of numerous training problems, practical examples, and case studies help the readers not only to find the answers to their current questions but also to get a common view of synchronization’s role in the modern telecommunications. The book is geared towards students of telecommunications but can also be useful for telecom engineers and for training/workshops for telecom engineers concerning synchronization topics.