Preface.- Intermittency in Turbulence (R. Benzi, L. Biferale).- The Problem of Turbulence and the Manifold of Asymptotic Solutions of the Navier-Stokes Equations (F. H. Busse).- Renormalization Methods Applied to Turbulence Theory (D. Mc Comb).- From Rapid Distorsion Theory to Statistical Closure Theories of Anisotropic Turbulence (C. Cambon).- Engineering Turbulence Models and their Development, with Emphasis on Explicit Algebraic Reynolds Stress Models (A. V. Johansson).- Symmetries and Invariant Solutions of Turbulent Flows and their Implications for Turbulence Modelling (M. Oberlack)