This review aims to steer a central course through the high Reynolds number theory of laminar flows, from its early classical beginnings and failures to its present-day status. The review is divided into three parts.
Part I concerns external flows. It deals in turn with the classical attached flow strategy and its deficiencies; the incompressible triple-deck structure; the compressible triple-deck, supersonic flow and breakaway separation; incompressible breakaway separation and applications; and, finally, other triple-deck situations and other external flow structures.
Part II concerns internal flows. Symmetric channel flows and axisymmetric pipe flows are considered first, followed by a discussion of non-symmetric channel flows and three-dimensional pipe flows.
Part III concerns recent work on special situations where the classical strategy is consistent with separation. This deals with: flow over an obstacle in a wall layer; marginal separation; and, finally, unsteady breakaway separation.