This introduction presents an overview of the key concepts covered in the subsequent chapters of this book. The book provides guidelines for device deployment of typical heterogeneous Wireless Sensor Networks (WSNs) in Outdoor Environment Monitoring (OEM) applications. It introduces a novel 3-D deployment strategy, called Optimized 3-D Grid deployment with Lifetime Constraint (O3DwLC), for relay nodes in environmental applications. The book proposes two Optimized Relay Placement (ORP) strategies with the objective of federating disjoint WSN sectors with maximum connectivity under a cost constraint on total number of relay nodes (RNs) to be deployed. It also proposes a 3-D grid-based deployment for RNs in which the relays are efficiently placed on grid vertices. The book presents a novel approach, named Fixing Augmented network Damage Intelligently (FADI), based on minimum spanning tree construction to reconnect disjointed WSN sectors. It proposes use of cognitive nodes (CNs) in the underlying sensor network to provide intelligent information processing and knowledge-based services to the end users.