Two major problems in modern theoretical high energy physics are the problem of obtaining an analytic formulation of the strong coupling dynamics of asymptotically free gauge theories and the problem of understanding the dynamics of gravity in the vicinity of spacetime singularities (e.g. black holes or cosmological singularities). The aim of the present project is to make progress in both problems with a parallel study of D-brane dynamics in string theory and black holes in gravity. Extracting non-trivial information about the strong coupling dynamics of (non)-supersymmetric gauge theories like QCD has proven a difficult task. Most examples of the holographic correspondence involve gauge theories with a high degree of symmetry and are restricted on the gravity side to the supergravity approximation, which for QCD-like theories is expected on general grounds to be fundamentally incomplete. In order to exploit the full scope of string dynamics one must go beyond this approximation. For QCD-like theories it has long been anticipated that the right setup involves string theories living in non-critical dimensions. Based on recent work in this topic, this investigation aims to make progress in this direction with a multi-faceted study of the exact stringy properties of D-branes in a well-established class of non-critical string theories, which have already been shown to incorporate interesting QCD-like theories. In parallel, we propose to examine other stringy aspects of the more traditional AdS/CFT correspondence. The second phase of the project concerns the second major problem outlined above. We propose a systematic study of the phases of black holes in higher dimensional gravity with a concrete set of methods. General relativity in higher dimensions is an active area of research and exhibits new fascinating aspects with possible applications in black hole physics and the AdS/CFT correspondence, but also possible experimental implications.