Strange attractors of forced one dimensional systems : existence and geometry Non smooth saddle node bifurcations of one parameter families of quasiperiodically driven dynamical systems on the real line give rise to strange non chaotic attractors. In this thesis we provide a class of families which has non empty interior in the C2 topology and whose elements undergo non smooth saddle node bifurcations. Within this class we study the geometry of the corresponding strange attractors by computing diﬀerent fractal dimensions. In particular we show that the Hausdorﬀ dimension diﬀers from the box counting dimension. We further obtain a description of the minimal set at the bifurcation as a maximal invariant set. Our results treat both the discrete and the continuous time case. A number of explicit examples emphasise the applicability of our ﬁndings.