This book is in reality what it appears to be,—a correspondence between two friends. The responsibility for its publication is mine. For some years, I had been taking a stronger and stronger interest in Mr. Atkinson's views on a group of subjects which I had been contemplating from my youth up, with incessant curiosity, and, till of late, slight satisfaction. Last year, I asked him to permit me to inquire of him, in some sort of sequence, about his researches into the nature and position of the Human Being; and the replies I have received seemed to me to require of us both the discharge of that great social duty,—to impart what we believe, and what we think we have learned. I therefore suggested the publication of our letters. Among the few things of which we can pronounce ourselves certain, is the obligation of inquirers after truth to communicate what they obtain: and there is nothing in the surprise, reluctance, levity, or disapprobation of any person, or any number of persons, which can affect that certainty. It may be, or it may not be, that there are some who already hold our views, and many who are prepared for them, and needing them. It is no part of our business to calculate or conjecture the reception that our correspondence is likely to meet with.