Mr. Thomas Whittaker when going through the proofs. I am also indebted for kind advice and cordial help to Professor Knight. Excepting the full draft of an Introductory Lecture on the History of Philosophy, which has been collated with students' note-books to form Lectures III-VI, the-author's own materials have been wrought up almost wholly in Part II. For instance, in the concluding three lectures on Kant they practically superseded my having recourse to reports of college lectures. It so happened that, although the professor had more than once had occasion to give college lectures on this subject, only one set of notes on Kant had come into my hands.