One of the themes of the book is the contrast between Teutonic, northern European values and the culture of the peoples of the Latin Mediterranean. The worship of false idols to which the Germans subscribe will, almost by necessity, bring sorrow and ruin to the German side of the family. German racism is mentioned in this book, although the theme of the superiority and purity of the Aryan race does not dominate the long list of indictments of German culture contained in the narrative. The reader is supposed to be persuaded that Latin culture is superior because it possesses — and relishes — strong humanistic values and a more highly developed aesthetic sense. These virtues, the book suggests, are worth fighting and dying for, even for young Julio Madariaga, an irresponsible and frivolous Argentine national inspired to fight on behalf of the French by a sense of the justness of their cause.

In The Four Horsemen of the Apocalypse, distorted and perverted notions of nationalism are allowed to triumph over common sense and family relations. This would never happen in the New World, the author implies, where open frontiers allow those of many nations to live and prosper together.

The antiwar theme dominates the second part of the book. It is clear, on the one hand, that the author abhors war and its consequences and attributes it to selfish and narrow motives such as a desire for power and territorial aggrandizement. On the other hand, he is not a pacifist; Blasco clearly believes that serving as a soldier in the war — when fighting on the side the French and their allies — is a noble and exemplary deed and a true measure of heroism.