 Given the vast scope and meticulous reasoning of Hartmann’s work, this entry cannot aspire to adequately present its rich content. But since Hartmann was a problem-oriented thinker, the task will be made easier by discussing the theses of his major works under the headings of the problems with which he was attempting to deal. In the remaining four sections, we will look at Hartmann’s responses to these questions: What is the relationship between thinking and being? What is valuable, and relatedly, what is the place of humankind in the world? What is the structure of the real world? Finally, in the Conclusion, What is Philosophy?, we will also very briefly consider Hartmann’s conception of philosophy in relation to that of his contemporaries.