The evolution of the disarmament regime of the 1972 Biological and Toxin Weapons Convention (BTWC) is described from 1980, when the first BTWC Review Conference was held, until 1998. The author analyses the results of our first four review Conferences; the meetings of the Ad Hoc Group of Governmental Experts to Identify and Examine Potential Verification Measures from a Scientific and Technical Standpoint; the 1994 Special Conference; the current negotiations of the Ad Hoc Group to produce an additional protocol the BTWC, which may include verification measures; handling of the 1997 Cuban allegation of US biological warfare; and the implementation of Article X of the BTWC on international transfers and cooperation for peaceful purposes. The strength of the BTWC regime is assessed in the light of its evolution through the review process and its changing contents, including Russia's admission that it had inherited an offensive biological weapon programme. The book applies an original sector-by-sector approach to its analysis of the BTWC, studied in a long-term perspective.