In smart cities, information and communication technologies are integrated to exchange real-time data between citizens, governments, and organizations. Blockchain provides security for communication and transactions between multiple stakeholders. Digital twin refers to a simulation of physical products in a virtual space. This simulation fully utilizes the physical models, wireless sensor networks, and historical data of city operation to integrate big information (digital twin cities) under multidiscipline, multiphysical quantities, multiscale, and multiprobability. Digital Twin, Blockchain, and Sensor Networks in the Healthy and Mobile City explores how digital twins and blockchain can be used in smart cities. Part 1 deals with their promising applications for healthy cities. Part 2 covers other promising applications and current perspectives of blockchain and digital twins for future smart society and smart city mobility. Together with its companion volume, Digital Twin and Blockchain for Sensor Networks in Smart Cities, this book helps to understand the vast amount of data around the city to encourage happy, healthy, safe, and productive lives.