This volume collects several studies on Anselm of Canterbury's philosophical theology and ethics originally presented at the Third International Conference of Medieval Philosophy at the Pontifical Catholic University of Rio Grande do Sul (PUCRS), Porto Alegre / Brazil, 02-04 September 2009. In commemoration of the 900th anniversary of Anselm's death, the conference facilitated a unique exchange of ideas among Latin American, North American and European scholars on current issues in Anselmian scholarship. The papers included in the volume concern diverse areas of interest: Anselm's method in different phases of his career and his attitude towards philosophy; Anselm's contribution to logic and semantics in De grammatico; the continuing challenge of interpreting his "proof" in Proslogion (revisited with an eye into contemporary accounts of his unum argumentum); the topic of guilt and punishment in Anselm's works, as well as the understanding of his moral-theological project, in dialogue with contemporary discussions of deontology; the fundamental aspects of his view on human being; the reception of Anselm's theory of perfections in Duns Scotus's metaphysics; and the place of Anselm's thought in Karl Barth's understanding of theology. These contributions, through their engagement with Anselm's works, seek to shed light on philosophical and theological of perennial interest. The volume contain the contributions of R.H. Pich (Porto Alegre), C. Viola (Paris), S. Magnavacca (Buenos Aires), J. Muller (Bochum), Th. S. Leite (Porto Alegre), G. Wyllie (Rio de Janeiro), J. M .C. Macedo (Porto), A. Culleton (Sao Leopoldo), M. Tracey (Lisle - IL), L.A. De Boni (Porto Alegre), G. K. Hasselhoff (Bochum).