Since the publication of his masterpiece "Expressive Rationality," Robert B. Brandom has been regarded as one of the most important philosophers of our time. In "Justification and Understanding," he now addresses his central theme in a concise manner, namely the clarification of the use and content of concepts. Starting from the thesis that the content of concepts is determined by their role in inference, Brandom achieves a surprising clarification of such important philosophical issues as the problems of normativity, intentionality, and representationality of thought and speech, as well as the objectivity of conceptual content. "Justification and Understanding" can be read as a prolegomenon to Brandom's philosophy.