Monograph describes the development of unified methods and software tools for Web resources processing in the Internet systems based on Web Mining and Natural Language Processing. The models of Web resource processing in Internet systems are proposed. Architecture and models of Internet systems are built. A new approach to application and implementation of business processes is formulated for the construction of Internet systems. A complex method of content formation, the operational method of content management and complex method of content support are developed. Software tools for content formation, management and support are developed. Design and implementation methods of Internet systems based on electronic content commerce systems, online newspapers and Internet tourism are developed. For the perspective of a systemic approach, the principles of applying Web resources processing in Internet systems for content lifecycle implementation in methods of the content formation, management and support are developed.