Reminiscences on science at I.H.E.S. A problem on homoclinic theory and a brief review

On the occasion of the 40-th anniversary of IHES I present a few scientific reminiscences: most of my scientific life has been marked by my visits and I run through them concluding with the analysis of a problem that originated during my last visit. The problem is to develop a convergent perturbative algorithm for the construction of the ``Eliasson's potential'' for the stable and unstable manifolds of an invariant torus: and to study its properties. A brief review follows.