This anthology collects a number of fascinating strands of Bertrand Russell's thought. "Mathematics and the Metaphysicians" details the impact of the 1900 World Congress of Philosophers on Russell's development and the hope that new methods in mathematics could be applied to the solution of ancient philosophical problems. Many of the subsequent essays show the evolution of this hope as Russell worked on the foundations of mathematics and applied the new methods to the reconstruction of physical objects on the basis of sense-data, and the redefinition of matter and cause.