The book opens with an “Introduction” that offers a comprehensive overview of IoT-based Wireless Sensor Networks (WSNs). It highlights a wide range of applications, from military use in battlefield monitoring to health applications in wearable patient monitoring, as well as environmental uses in water and air monitoring, and agricultural applications like greenhouse and livestock farming. However, the chapter acknowledges that the design and deployment of IoT-based WSNs come with notable constraints such as limited processing power, memory, connectivity, and battery capacity. The dynamics of these networks are shaped by a multitude of factors, which include the communication medium, resource limitations, node deployment, energy considerations, data reporting model, node/link heterogeneity, coverage and connectivity, fault tolerance and self-organization, scalability, network dynamics, transmission media, data aggregation, QoS requirements, mobility, and deployment. Regardless of these challenges, the chapter underscores the critical role of IoT-based WSNs across diverse sectors, highlighting their potential to transform the way we monitor and interact with our surroundings.