The present collection of reprints covers the main contributions of David Ruelle, and coauthors, to the theory of chaos and its applications. Several of the papers reproduced here are classics in the field. Others (that were published in less accessible places) may still surprise the reader.The collection contains mathematical articles relevant to chaos, specific articles on the theory, and articles on applications to hydrodynamical turbulence, chemical oscillations, etc.A sound judgement of the value of techniques and applications is crucial in the interdisciplinary field of chaos. For a critical assessment of what has been achieved in this area, the present volume is an invaluable contribution.Contents:On the Nature of TurbulenceBifurcation in the Presence of a Symmetry GroupThe Ergodic Theory of Axiom A FlowsMicroscopic Fluctuations and TurbulenceStrange AttractorsMeasures Describing a Turbulent FlowDo Turbulent Crystals Exist?Characteristic Exponents for a Viscous Fuid Subjected to Time Dependent ForcesBowen's Formula for the Hausdorff Dimension of Self-Similar SetsErgodic Theory of Chaos and Strange AttractorsLiapunov Exponents from Time SeriesFundamental Limitations for Estimating Dimensions and Lyapunov Exponents in Dynamical SystemsWhere can One Hope to Profitably Apply the Ideas of Chaos?Readership: Nonlinear scientists, researchers in fluid dynamics, mathematical physicists and mathematicians.Key Features:Freely-expressed scientific point of views on the most important contemporary and future emergencies facing humanity