The high energy behaviour of string theory has been attracting attention ever since its beginnings. In this talk I will focus on the Regge regime and discuss in particular the scattering of a highly energetic pertubative string state against a stack of D-branes. I will compare different points of view: the field theory limit, the analysis in terms of flat space string amplitudes, and finally the description in terms of a curved background. I will suggest that these approaches can contribute to shed light (or at least formulate precisely) some basic problems of black hole physics.