A sequence of lectures offers a systematic, critical history of philosophy, opening with an account of the notion, sources, and method appropriate to writing such a history and with remarks on philosophy’s relation to other fields. The work then surveys early Asian thought before turning to ancient Greek developments, presenting pre-Socratic inquiries, Pythagorean and Eleatic positions, Heraclitean and atomist approaches, and the rise of the Sophists and Socratic method, followed by the diverse schools that interpret and extend Socratic ideas, each discussed in relation to the broader evolution of philosophical concepts.