London: Parker, Son and Bourn, 1863. First Edition. Very Good. 95 pp. + 4 [ads]. First edition, first printing. Bound in publisher's original plum cloth, with spine lettered in gilt, neatly rebacked with loss to several gilt letters. Small, previous owner name written on title page. Contents mildly toned with light, sporadic foxing. "Small books are so much more read than large ones that it is an advantage when one's matter will go into a small space." -John Stuart Mill in a letter to a friend [Collected Works XV, p. 645]. A slim volume by design that sparked a revolution within moral philosophy, comprised of an essay in three articles that first appeared in Fraser's Magazine two years earlier. It is now generally regarded as one of the most significant works of the 19th century in any field and continues to be widely read.