Tms volume is from the pen of the late Thomas Martin Herbert, m.a., Professor of Philosophy and Church History in Lancashire Independent College. He died at the early age of forty-two, in November, 1877, after one day's illness, having occupied this post for little more than twelve months. The sub ject treated of in this book was thoroughly congenial with his tastes. For years he had given it careful attention, devoting to it all the time he could com mand. His first published thoughts upon the sub ject appeared in the British Quarterly Review for January, 1874, in an article entitled Mind and the Science of Energy. The reception with which that article met confirmed his sense of the importance of his argument, and encouraged him to carry out his intention of more fully developing his thoughts in the form in which they are now laid before the public. The task of editing the book has been undertaken by his colleague, James M. Hodgson, m.a., b.d. Except the correction of some clerical errors, and slight changes in a few sentences manifestly obscure or incorrect, which Mr. Herbert would doubtless have altered had he lived, the treatise has been published as nearly as possible in the form in which he left it. The reader must, however, bear in mind that the manuscript had undergone no final revision for the press by its author. Had this been the case no doubt sundry alterations would have been made, including the re casting of some sections, the erasure of occasional unnecessary repetitions, and the addition of some closing paragraphs which there is proof the author intended to write. The division of the matter into chapters and sections is the work of the editor.