Since the early days of antiquity, epistemology, ontology, and metaphysics are fundamental fields of philosophical inquiry. The concept of knowledge is the main topic of epistemology, whereas that of ontology and metaphysics is the concept of being. This course aims to acquaint the students with some of the main ideas and theories in contemporary philosophical debates. In the first part, the concept of knowledge will be introduced. Particular attention will be given to the concept of justification and to the variety of standpoints from which it could be approached. In the second part we will examine some metaphysical problems: the-mind-body problem, personal identity, time and becoming, free will and determinism, etc.