Recent advances in boundary-layer theory have shown how modern analytical and computational techniques can and should be combined to deepen the understanding of high Reynolds number flows and to design effective calculation strategies. This is the unifying theme of the present volume which addresses laminar as well as turbulent flows.Dedicated to Prof. W.Schneider on the Occasion of his 60th BirthdayK. Gersten: Introduction to Boundary-Layer Theory.- H. Herwig: Laminar Boundary Layers: Asymptotic and Scaling Considerations.- R.J. Bodonyi: Boundary-Layer Stability Asymptotic Approaches.- H. Herwig, J. Severin: The Effect of Heat Transfer on Flow Stability.- K. Gersten: Turbulent Boundary Layers I: Fundamentals.- J.D.A. Walker: Turbulent Boundary Layers II: Further Developments.- A. Kluwick: Interacting Laminar and Turbulent Boundary Layers.Springer Book Archives