This book considers dense wireless sensor networks that are designed for applications with continuous data delivery models, where sensors periodically report to a base-station or a data processing center. Since wireless communication is considerably more energy-expensive than signal processing or computing, we tackle the problem using three different energy-conserving techniques: clustering, which improves the communication efficiency, node scheduling, which obviates wasteful data transmission and sensing, and distributed data compression, which reduces the wireless transmitted data volume. All the developed algorithms and protocols are distributed and localized, requiring no global knowledge, central control or request-and-acknowledge iterations, and hence scales very well with large network sizes.