This book constitutes the refereed proceedings of the Fourth International AMAST Workshop on Real-Time Systems and Concurrent and Distributed Software, ARTS'97, held in Palma de Mallorca, Spain, in May 1997. The volume presents 24 carefully selected revised full papers. Also included are two historical contributions honoring Ramon Llull, who was born on Mallorca, as well as two invited papers. All current issues in the field of formal methods for...