This chapter provides an in-depth examination of Smart and Connected Health (SCH), emphasizing the foundational technologies and system architectures that enable intelligent, scalable, and patient-centric healthcare solutions. It begins with a comprehensive treatment of the Internet of Things (IoT), covering the full stack from smart sensing devices and actuators to communication protocols and network architectures. The discussion then extends to Edge-Fog-Cloud computing paradigms, highlighting their role in improving latency, resilience, and context-awareness in time-sensitive healthcare applications. In addition, the chapter explores software architectural models—including layered, service-oriented, event-driven, and microservices-based frameworks—that support modularity, scalability, and real-time processing. Together, these components form an integrated technological ecosystem capable of addressing the operational, analytical, and infrastructural demands of modern digital health systems.