Contents: I. Ekeland: The -variational principle revisited.- P. Marcellini: Non convex integrals of the calculus of variations.- A. Marino, M. Tosques: Some variational problems with lack of convexity and some partial differential inequalities.- Cz. Olech: The Lyapunov theorem: its extensions and applications.- G. Pianigiani: Differential inclusions. The Baire category method.- R.T. Rockafeller: Nonsmooth analysis and parametric optimization.- M. Valadier: Young measures.- List of participants.

The ?-variational principle revisited.- Non convex integrals of the Calculus of Variations.- Some variational problems with lack of convexity and some partial differential inequalities.- The Lyapunov Theorem: Its extensions and applications.- Differential inclusions the baire category method.- Nonsmooth analysis and parametric optimization.- Young measures.