Stanford Encyclopedia of Philosophy (SEP) is a dynamic reference work satisfying high academic standards. Maintained by a group of experts in the field at the University of Stanford and with 3 mirror sites in the world, it is based on an asynchronous activity of updating and peer-refereeing. SEP collects hundreds of articles mostly philosophy-centered but covering a comprehensive set of topics. Its website gives access to the SEP “fixed editions”, which are the successive versions of the encyclopedia updated, modified and compiled on a quarterly basis. SEP also shows two kinds of tables of contents: entries that are published or assigned, and entries which are still unassigned but nevertheless projected. All materials are available entirely free of charge and with very high updating rate, usually on a weekly basis. An added value are the cross-references among the edited concepts and entries, as well as by pertinent connections to external websources. Special sections explain how to cite this encyclopedia and offer detailed editorial information. A simple search feature is provided to locate entries, which can be saved on screen or downloaded by a SEP offprint mode. Thanks to a simple interface design and a textual mapping, this website represents an authoritative research tool for philosophers and human scientists.