This course covers the basic technology underlying web search engines and related tools. The main focus will be on large-scale web search engines (such as Google, Yahoo, and MSN Search) and the underlying architectures and techniques. Students will learn how search engines work, and get hands-on experience in how to build search engines from the ground up. Topics are taught based on a reading list of recent research papers. Students have to work on a course project and may have to present in class.