The present volume, Three Philosophical Poets, is composed, with a few additions, of six lectures read at Columbia University in February, 1910, and repeated in April of the same year, at the University of Wisconsin. These lectures, in turn, were based on a regular course which I had been giving for some time at Harvard College. Though produced under such learned auspices, my book can make no great claims to learning. It contains the impressions of an amateur, the appreciations of an ordinary reader, concerning three great writers, two of whom at least might furnish matter enough for the studies of a lifetime, and actually have academies, libraries, and university chairs especially consecrated to their memory. I am no specialist in the study of Lucretius; I am not a Dante scholar nor a Goethe scholar. I can report no facts and propose no hypotheses about these men which are not at hand in their familiar works, or in well-known commentaries upon them. My excuse for writing about them, notwithstanding, is merely the human excuse which every new poet has for writing about the spring. They have attracted me; they have moved me to reflection; they have revealed to me certain aspects of nature and of philosophy which I am prompted by mere sincerity to express, if anybody seems interested or willing to listen. What I can offer the benevolent reader, therefore, is no learned investigation. It is only a piece of literary criticism, together with a first broad lesson in the history of philosophy-and, perhaps, in philosophy itself.