The author was a priest in the Catholic Church and subsequently left it as he slowly lost faith in its teachings. He then began a life-long literary career until his death in 1955. He translated over 200 books and some 300 titles under Haldeman-Julius Publications and became know as the "world's greatest scholar."
Stein, in his "God Pro and Con," lists this work as "probably the scarcest McCabe book." p. 172, # 1759. I did a Worldcat search for this title on September 3, 2013 and found only 12 libraries in the world have a copy of this volume.
McCabe argues that the religion of the twentieth century will not only not be like the previous centuries but that, eventually, it will fade away. He offers several reason for this belief. He writes "The first is the decay of asceticism. The most cursory examination of the teaching of Christ reveals its profoundly ascetical character. Voluntary poverty, voluntary celibacy, and self-denial of every kind are preached on every page of the Gospels. The modern world will not have asceticism; it ridicules the idea. The Church of Rome and advanced Anglicanism faintly uphold it in theory, but the practice is in a fair way of extinction. The second feature is the humanization of the Churches, of which we have spoken. These two features not only point to a general decay of dogma and to a growing laxity of attitude in face of "revealed truth," but they greatly increase the significance of the figures we have cited above. They have made submission to the Churches infinitely easier, yet they have not prevented so widespread a defection. The third feature is the strong representation of heterodoxy in literary circles. It is well known that Agnosticism is very ably represented among our scientists, historians, essayists, and novelists. If we may take the proportion of heterodoxy among our writers as the true proportion of heterodoxy among educated people, we must conclude that the decline of theological religion has proceeded far indeed."
"Since these tendencies have been steadily increasing throughout the century --- the Churches having consistently narrowed their spheres and modified their dogmas --- the religion of the twentieth century is not difficult to forecast. It is far from likely that dogmatic religion will disappear in the course of a century, but we may safely anticipate a consistent
progress of its decline. A strong effort will be made by professional ecclesiastics at the commencement of the century, and progress will be temporarily impeded. But they have no sound philosophy, no tangible "evidences" to satisfy the demand that Rationalism has created, and their appeal to emotion cannot have an enduring effect in an age of greater education. Slowly, but surely, the vision of God and of immortality will fade from the mind of the race, and it will pour out its enthusiasm before the altar of an ethical and purely human idealism." p. 102.