Source : Free On-Line Dictionary of Computing

B-Method
     
         A system for rigorous or formal
        development of software using the notion of {Abstract
        Machine}s to specify and design software systems.  The
        B-Method is supported by the {B-Toolkit}.
     
        Abstract Machines are specified using the Abstract Machine
        Notation (AMN) which is in turn based on the mathematical
        theory of {Generalised Substitution}s.
     
        (1995-03-13)