This thesis is a chronological study of Broch's work from the early 1930's until his death in 1951. The former date is selected as the point of departure because, with the publication of "Der Zerfall der Werte" in Die Schlafwandler in 1932, Broch, for the first time, gave definitive expression to his theory of values, which he had been gradually formulating in years of research prior to that date. There are two main parts to this study. Broch's theoretical writings are first examined with a view to showing how and why the theory of "das Irdisch-Absolute" developed and to explaining exactly what it is. In the second part his novels are examined with the aim of establishing the extent to which the developing theory of "das Irdisch-Absolute" is reflected in them. It can be shown that the basic development in question is a progression in Broch's thinking from reliance on the purely formal, abstract, transcendental Absolute of the Logos to the conviction that man, as the empirical, earthly Absolute, must be the final criterion by and against which all values must be judged. The main purpose of the thesis, as explained in the introduction, is to show how Broch, an intellectual and theoretician, was forced by historical circumstances continually to modify and revise his thinking on the basic question of ethics. This revision, of which Broch was never fully aware himself, is seen in the way he progressively abandoned a highly abstract, theoretical and speculative conception of ethics, which seemed to have little immediate relevance to the problems of his own generation, in favour of a more practical morality of direct humanitarian commitment.