The volume presents the proceedings of the international symposium, fruit of a common research project engaged in by 48 scholars, that took place in Rome to celebrate the 8th centennial of Saint Bonaventure's birth. The theme, "Deus summe cognoscibilis", could sound, in the contemporary agnostic, secular context, like a provocation. The approach, however, of the symposium was to consider "the current theological relevance of Saint Bonaventure", focusing on thinking with our author about a number of themes: theological method (philosophy, theology and mysticism); revelation (in Scripture and history); creation (in Laudato si' and evolution); Christology (the triplex Verbum and logos of the Cross); ecclesiology and Trinitarian dimensions of sacramental theology; pre-phenomenological Trinitarian theology, and our own divine filiation. An appendix contains a previously unpublished text of J. Ratzinger about Bonaventure's theological method. The volume has also two indexes (authors' names and references to the works of Bonaventure).