 Russell’s most important writings relating to these topics include Knowledge by Acquaintance and Knowledge by Description (1911), The Problems of Philosophy (1912a), “Our Knowledge of the External World” (1914a), On the Nature of Acquaintance (1914b, published more completely in Collected Papers, Vol. 7), “The Philosophy of Logical Atomism” (1918, 1919), “Logical Atomism” (1924), The Analysis of Mind (1921), The Analysis of Matter (1927a), Human Knowledge: Its Scope and Limits (1948), and Theory of Knowledge (CP, Vol. 7).