Dissipative dynamical systems with many degrees of freedom naturally evolve to a self‐organized critical state with fluctuations (avalanches) extending over all length‐ and time‐scales. The systems operate at the border of chaos, with zero Lyapunov exponent and algebraic growth of initial deviations. This picture has support from numerical and analytical model calculations, and from experiments by Held on sandpiles, by Babcock and Westervelt, and by Che and Suhl on magnetic domain patterns, and by God on earthquakes. Applications to turbulence, biology, and economics have been suggested.