On-line information -- and free text in particular -- has emerged as a major, yet unexploited, resource available in raw form. Available, but not accessible. The lexicon provides the major key for enabling accessibility to on-line text. The expert contributors to this book explore the range of possibilities for the generation of extensive lexicons. In so doing, they investigate the use of existing on-line dictionaries and thesauri, and explain how lexicons can be acquired from the corpus -- the text under investigation -- itself. Leading researchers in four related fields offer the latest investigations: computational linguists cover the natural language processing aspect; statisticians point out the issues involved in the use of massive data; experts discuss the limitations of current technology; and lexicographers share their experience in the design of the traditional dictionaries.