Book excerpt: This book constitutes the strictly refereed post-proceedings of the 5th International Hybrid Systems Workshop held in Notre Dame, Indiana, USA in September 1998. The 23 revised full papers presented in the book have gone through two rounds of thorough reviewing and revision. The volume presents state-of-the-art research results and particularly addresses such areas as program verification, concurrent and distributed processes, logic programming, logics of programs, discrete event simulation, calculus of variations, optimization, differential geometry, Lie algebras, automata theory, dynamical systems, etc.