When I issued the first volume of "Lectures to my Students" it was my intention to prepare another series as soon as time permitted, and I meant to include two addresses upon Commenting in the proposed selection. It struck me, however, that a better thing was possible. The two lectures might introduce the topic of exposition, and then a catalogue of Commentaries might help the student to carry the advice into practice. The making of that catalogue would, of course, be no small labor; but, once accomplished, it might be of service to many, and effect more in the direction aimed at than the most earnest exhortations. I therefore resolved to attempt the work, and here is the result.