Chaos in systems beyond hyperbolicity

We give a survey of recent results on dynamical systems with chaotic behaviour which are not hyperbolic, and, in particular, which are derived in some way from the Hénon attractor. The type of attractors we discuss are sometimes called Henon-like attractors. Numerical simulations seem to indicate that these attractors occur quite generally. They have been shown to occur, under rather general assumptions, in unfoldings of homoclinic tangencies.