Book excerpt: This book is the proceedings of the Workshop on the Performance Engineering of Computer and Telecommunications Systems. The workshop Was held at Liverpool John Moores University, England on the 5th and 6th September 1995. The workshop follows a series organised by the British Computer Society (BCS) Special Interest Group on Performance Engineering. The workshop addressed most techniques and experieI1ces in the Engineering of Computer and Telecommunications Systems that provide a guaranteed quality of service. Techniques such as measurements, simulation, and analytical models and their applications to ATM networks, Multimedia Systems, Distributed Systems, Access and Wide Area Networks were presented. In addition a number of papers dealt with advances in the development of analytical models, simulation architectures and the application of formal methods, stich as Process Algebra, to the specification and building of performance biased computer systems. The book is suitable for systems designers, engineers, researchers and postgraduate students interested in the design and implementation of Computer Systems, Networks and Telecommunications. Many people assisted in the arrangements and success of this workshop. I would like to thank them all and in particular the reviewers. I would also like to particularly thank our industrial sponsors GPT Public Networks Group, Liverpool and BICC Cables, Chester, England for their generous financial and material support.