Existence of huge amounts of data on the Web has developed an undeferring need to locate right information at right time, as well as to integrating information effectively to provide a comprehensive source of relevant information. There is a need to develop efficient tools for analyzing and managing Web data, and efficiently managing Web information from the database perspective. The book proposes a data model called WHOM (Warehouse Object Model) to represent HTML and XML documents in the warehouse. It defines a set of web algebraic operators for building new web tables by extracting relevant data from the Web, as well as generating new tables from existing ones. These algebraic operators are used for change detection.