Published in 1899, this first volume of what many consider Royce's masterwork expands upon his Gifford Lectures, delivered at Aberdeen University in January and February of that year. Grouped under the topic title "The Four Historical Conceptions of Being," these ten essays include "The Religious Problems and the Theory of Being," "Realism and Mysticism in the History of Thought," and "Individuality and Freedom." The book also contains a supplemental essay, "The One, the Many, and the Infinite." (A second volume, based on a second series of Gifford lectures, given the following year, were published in book form in 1901.)