Never before, since the era of Gutenberg, has an invention provided individuals with a capability to access information that is more powerful and far-reaching than Web Search Engines. The Search Engine invention, however, would not have been made possible in the absence of advances in different areas of Computer Science (algorithms, data-structures, computer systems, etc).

The objective of this course is to examine the main computer science principles that lie behind Google and other search engines. To this end, we will provide an introduction to Information Retrieval (IR), which is described as "the science of searching for information in documents, searching for documents themselves, searching for metadata which describe documents, or searching within databases, whether relational stand-alone or hypertextually-networked such as the World Wide Web" (see Wikipedia).

During the course, we will focus on basic and advanced techniques for text-based information systems: efficient text indexing; Boolean and vector space retrieval models; evaluation and interface issues; text classification and clustering. We will also examine Web search including crawling, link-based algorithms, and Web metadata. The course is aimed at early-stage postgraduate students of computer science and senior computer science undergraduates as well as students from statistics, linguistics, and various engineering principles. The language of instruction is greek but most of the educational material (book, slides, web pages) will be in english.

Basic prerequisites are: an introductory course in data structures and algorithms, in linear algebra and in probability theory, and in databases. A good knowledge of the Java programming language will be helpful with programming assignments.