Integrability and matrix models

The theory of matrix models is reviewed from the point of view of its relation to integrable hierarchies. Discrete 1-matrix, 2-matrix, 'conformal' (multicomponent) and Kontsevich models are considered in some detail, together with the Ward identites ('W-constraints'), determinantal formulas and continuum limits, taking one kind of model into another. Subtle points and directions of the future research are also discussed.