Every five years the Permanent International Committee of Linguists (CIPL) organises a world congress for linguists. And every five years the Committee faces the challenge of presenting a programme at the highest possible level. The CIPL Executive Committee decided for the Congress planned for 2003 in Prague to focus on four major topics which play an important role in today’s linguistic debate: 1. Typology, 2. Endangered Languages, 3. Methodology and Linguistics (including fieldwork) and 4. Language and the mind. Leading experts have introduced the four themes in their plenary lectures in the course of the congress, which served as a basis for the articles presented in the current volume.