This book provides a comprehensive treatment of the performance evaluation of UAV communication systems, using stochastic geometry to explore the impact of the random positions of UAVs on transmission performance. The book focuses on engineering practice, with both modeling and analysis of UAV communication systems. It offers an in-depth study of several important UAV communication application scenarios, including UAV-terrestrial communication, UAV-to-UAV communication, satellite-UAV communication, and UAV relay communication.One of the key features of the book is its systematic approach to addressing UAV communication issues and providing practical insights. The book is especially useful for readers interested in learning how to model and analyze the performance of UAV communications systems. It will benefit researchers, engineers, and graduate students in the fields of wireless communications, signal processing, and related areas.