Declarative Networking is a programming methodology that enables developers to concisely specify network protocols and services, which are directly compiled to a dataflow framework that executes the specifications. Declarative networking proposes the use of a declarative query language for specifying and implementing network protocols, and employs a dataflow framework at runtime for communication and maintenance of network state. The primary goal of declarative networking is to greatly simplify the process of specifying, implementing, deploying and evolving a network design. In addition, declarative networking serves as an important step towards an extensible, evolvable network architecture that can support flexible, secure and efficient deployment of new network protocols. This book provides an introduction to basic issues in declarative networking, including language design, optimization and dataflow execution. The methodology behind declarative programming of networks is presented,including roots in Datalog, extensions for networked environments, and the semantics of long-running queries over network state. The book focuses on a representative declarative networking language called Network Datalog (NDlog), which is based on extensions to the Datalog recursive query language. An overview of declarative network protocols written in NDlog is provided, and its usage is illustrated using examples from routing protocols and overlay networks. This book also describes the implementation of a declarative networking engine and NDlog execution strategies that provide eventual consistency semantics with significant flexibility in execution. Two representative declarative networking systems (P2 and its successor RapidNet) are presented. Finally, the book highlights recent advances in declarative networking, and new declarative approaches to related problems. Table of Contents: Introduction / Declarative Networking Language / Declarative Networking Overview / Distributed Recursive Query Processing / Declarative Routing / Declarative Overlays / Optimization of NDlog / Recent Advances in Declarative Networking / Conclusion.