This book constitutes the refereed proceedings of the First International Conference of B and Z Users, ZB 2000, held in York, UK in August/September 2000.The 25 revised full papers presented together with four invited contributions were carefully reviewed and selected for inclusion in the book.

Meeting the Challenge of Object-Oriented Programming.- A Formal Mapping between UML Models and Object-Z Specifications.- A Generic Process to Refine a B Specification into a Relational Database Implementation.- Recursive Schema Definitions in Object-Z.- On Mutually Recursive Free Types in Z.- Reasoning Inductively about Z Specifications via Unification.- Reconciling Axiomatic and Model-Based Specifications Using the B Method.- Compositional Structuring in the B-Method: A Logical Viewpoint of the Static Context.- Automatic Construction of Validated B Components from Structured Developments.- Playing with Abstraction and Refinement for Managing Features Interactions.- A Formal Architecture for the 3APL Agent Programming Language.- How to Drive a B Machine.- Deriving Software Specifications from Event Based Models.- Reformulate Dynamic Properties during B Refinement and Forget Variants and Loop Invariants.- Type-Constrained Generics for Z.- Typechecking Z.- Guards, Preconditions, and Refinement in Z.- Retrenchment, Refinement, and Simulation.- Performing Algorithmic Refinement before Data Refinement in B.- Program Development and Specification Refinement in the Schema Calculus.- Are Smart Cards the Ideal Domain for Applying Formal Methods.- Formal Methods for Industrial Products.- An Execution Architecture for GSL.- A Computation Model for Z Based on Concurrent Constraint Resolution.- Analysis of Compiled Code: A Prototype Formal Model.- Zzzzzzzzzzzzzzzzzzzzzzzzzz.- Segregation with Communication.- Closure Induction in a Z-Like Language.- Fuzzy Concepts and Formal Methods: A Fuzzy Logic Toolkit for Z.