This translation was undertaken in the belief that there are many English-speaking people who feel more than a merely superficial interest in ethical research, but who may not read German with sufficient ease to make them care to take up the original. The present Essay is one of the most important contributions to Ethics since the time of Kant, and, as such, is indispensable to a thorough knowledge of the subject. Moreover, from whatever point of view it be regarded, whether the reader find, when he closes the book, that his conviction harmonises with the conclusion reached, or not; it would be difficult to find any treatise on Moral Science more calculated to stimulate thought, and lift it out of infantile imitation of some prescribed pattern. The believer in the Kantian, or any other, basis of Ethics, could hardly measure the strength or the weakness of his own position more surely than by comparing it with the Schopenhauerian; while he who is yet in search of a foundation will find much in the following pages to claim his attention.