Enzo Olivieri, Elisabetta Scoppola METASTABILITY AND TYPICAL EXIT PATHS IN STOCHASTIC DYNAMICS (81K, TeX) ABSTRACT. (Proceedings of ECM2) In this paper we review and discuss results on metastability. We consider ergodic aperiodic Markov chains with exponentially small transition probabilities and we give a complete description of the typical tube of trajectories during the first excursion outside a general domain $Q$.