Remarks on turbulence theory.- Hydrodynamic visualization of organized structures and turbulences in boundary layers, wakes, jets or propellor flows.- I. Free Shear Flows.- The emergence of characteristic (coherent?) motion in homogeneous turbulent shear flows.- Generation of coherent structures in free shear layers.- Use of the proper orthogonal decomposition in a plane turbulent mixing layer.- On the three-dimensional dynamics of coherent structures forming in free, shear flows.- Visualizations of helium jets in air.- Thermal striping: structures in interacting jets.- II. Boundary Layers.- Three-dimensional aspects of the organized motion in a turbulent boundary layer.- Large-eddy simulation of boundary layers with a step change in pressure gradient.- III. Fundamentals.- Intermittent structure of dissipation in isotropic turbulence viewed from a direct simulation.- The spatial structure of homogeneous turbulence at Reynolds numbers around 1000.- Wavelet analysis of fully developed turbulence data and measurements of scaling exponents.- How solenoidal can be the Lamb vector in turbulent flow? Consequences and implications.- IV. Chaos and Instablity.- Bifurcations and bursting of streaks in the turbulent wall layer.- The dynamics of organized structures in the axisymmetric jet mixing layer.- Instability of the rectangular duct flow and generation of the secondary flow.- V. Vortex Breakdown.- Vortex breakdown: a coherent transition trigger in concentrated vortices.- Numerical simulation of vortex breakdown via 3-D Euler equations.- VI. Two-dimensional Turbulence.- The coherent vortices of two-dimensional and geostrophic turbulence.- Experiments on forced, quasi-two-dimensional turbulence at upwelling fronts.- Merging of two-layer baroclinic vortices.- Transmission of acoustic waves through mixing layers and 2D isotropic turbulence.- VII. Geophysical Fluid Dynamics.- Spectra and correlation functions of surface layer atmospheric turbulence in unstable thermal stratification.- Organized structures in strongly stratified flows.- Fossile and active turbulence.- Coherent structures in stratified turbulent shear flows deduced from direct simulations.- Influence of a shear on a stably-stratified flow.- Gravity wave patterns in the wake of a sphere in a stratified fluid.- VIII. Compressible and Reacting Flows.- The compressible mixing layer.- Numerical simulations of supersonic plane Couette flow instability.- Reactive scalar as a tracer of organized structures in turbulent mixing layers.- IX. MHD Turbulence.- Large-eddy simulation of MHD turbulent channel flow under a uniform magnetic field.- Coherent structures in MHD turbulence and turbulent dynamo.- List of Participants.- Author Index.- Colour Plates.