This pamphlet of 194 pages is the continuation of another pamphlet on August Comte, the founder of Positivism, which was reviewed in _The Open Court_, No. 134. The author is a Jesuit and it is a matter of course that all the facts he relates, all the doctrines he explains are represented from the standpoint of Roman Catholicism. The booklet is of great importance in so far as we learn through it what an erudite Catholic mind thinks of that recent movement of philosophy which has been called by the collective name Positivism. The method pursued by Hermann Gruber is most recommendable. He states facts and quotes abundantly so as to let the various philosophers speak for themselves. He is economical with the salt of his own opinion, yet he uses it with such a discretion that Roman Catholics can become thoroughly acquainted with infidel views without suffering in their faith. The book consists of two parts: (I) The Positivism of the schools in connection with Comte and of the Positivistic movement outside of these schools. The first part begins with a discussion of Littré. Littré, “the voice, the spirit and the soul of Positivism,” as Bourdon calls him, is characterised as a philological genius. Although he had chosen the medical profession, which however he abandoned early, and although he regarded the propaganda of the positive philosophy as his life-work, all his talents lay in the direction of special investigation in the literary, historical, and linguistic fields, and the editing of the French dictionary remains his main achievement.