generalizations upon society, he rises to make the duty of the individual most solemn and imperative. Above all, he has this best prerogative of really great thinkers,--he is able to change sentiments to convictions. If we have not particularized the claims of the single volume whose title is at the head of our notice, it is because all that Mr. Spencer has written moves towards one end and is equally worthy of attention. The essays here given are selected from two series, the first published in 1857, the second in 1863. The present arrangement has been chosen by the author as more suitable to develop the general purpose which governs his work. While the doctrine of Evolution is more or less illustrated in each of these papers, the variety of subjects discussed must touch at some point the taste and pursuit of any reader. From "Manners and Fashion" to "The Nebular Hypothesis" is a sweep bold enough to include most prominent topics with which we are concerned. Indeed, we can recall no modern volume of the same size which so thoroughly credits its author with that faculty of looking about him which Pope thought it was man's business to exercise. There are the current phrases, "seeing life," and "knowing the world," which generally used to signify groping in the dirtiest corners of the one and fattening lazily upon the other; but if it were possible to rescue such expressions from their vulgar associations, we think that a candid reader would apply the best conceptions they suggested to the writer of the discussions here collected. The world as it is to-day is seen by Mr. Spencer as by few living men. The sciences, which taken singly too often seem only good to expel the false, have been summoned together to declare the true. Not Nature alone, but Humanity, which is greater than Nature, must be interrogated for answers that shall satisfy the ripest reason of the age. By the rare gifts of comparison which turn to account his wide observations, Mr. Spencer has already established principles which, however compelled for a time to compromise with prejudices and vested interests, will become the recognized basis of an improved society.