This manuscript is a description of the research activities of the Lessico Intellettuale Europeo. The Centre works on the lexicographical analysis of philosophical and scientific texts, mainly of the seventeenth and eighteenth centuries. An important project is the Philosophical Dictionary of the Seventeenth and Eighteenth Centuries. The LIE series of publications include a number of indices, concordances and lexicons. Another project at the Centre is the Thesaurus Mediae et Recentioris Latinitatis. The Centre also publishes the proceedings of the three-yearly Colloqui internazionali.