The Philosophy of Knowledge, or Epistemology, explores the nature, sources, and limits of knowledge. It seeks to answer fundamental questions such as 'What is knowledge?' and 'How do we acquire it?'. Philosophers like Plato and Descartes have significantly contributed to this field, examining the distinction between belief and true knowledge. In addition to defining knowledge, the Philosophy of Knowledge also investigates the justification of beliefs. This involves understanding how we can justify our claims to know something, which is crucial in distinguishing between mere opinion and genuine knowledge. The works of Gettier have further challenged traditional views on justification.