Digital twin, blackchain, and wireless sensor networks can work together to improve services in the smart city. Big data derived from wireless sensor networks can be integrated to accommodate the exchange of real-time data between citizens, governments, and organizations. Blockchain can provide high security for large-scale communications and transactions between many stakeholders. Digital twin uses physical models and historical data to integrate big information under multidiscipline, multiphysical quantities, multiscale, and multiprobability conditions. Digital Twin and Blockchain for Sensor Networks in Smart Cities explores how digital twin and blockchain can be optimized to improve services. This book is divided into three parts. Part 1 focuses on the fundamental concepts of blockchain and digital twin for sensor networks in the smart cities, while Part 2 describes their applications for managing the regular operations and services. Part 3 deals with their applications for safe cities.