Authors who are not frivolous give careful thought to the titles of their books and of the chapters of their books. What is more, even careless authors are likely to give unwitting indications in their book and chapter titles as to the bottom of their thought. Present-day students often look upon study as a computer-assisted, if not a computer-dominated, acquisition of “data.” It might not occur to such a student to take careful note of book and chapter titles and to begin immediately to engage the author in argument. The title of this chapter should raise problems for the reader who is serious. Martin Heidegger (1889–1976), regarded by many as the greatest figure in philosophy in the twentieth century, gave a lecture in 1955 that was published shortly thereafter under the title, Was ist das – die Philosophie? (What Is This – Philosophy?). Thus, a figure so highly regarded looked upon the nature or the definition of philosophy as a question, a question the confrontation of which required study and argument. Consequently, beginning with the chapter title “What Philosophy Is” rather than “What Is Philosophy?” seems to suggest that I believe I know the answer to the question and can impart it to a beginning student. Given the fact that someone of Heidegger's stature regards what philosophy is as questionable, an author who seems to take an opposite view appears to be as foolish as someone who questions Darwin, Einstein, or Freud; or who wonders whether there is in fact global warming; or who questions whether sexual harassment, cigarette smoking, and failure to recycle are indeed the crimes of the century. We are handling two-edged swords here, however. If sexual harassment is as great a crime as many think, then Heidegger's character comes immediately into question because, in his thirties, and while married, he began a sexual liaison with one of his students who was eighteen and continued that liaison for some time. What is more, he was an open supporter of the Nazis for no small part of his life. Should we not dismiss whatever it is that Heidegger thinks and prefer another's views?