The key concepts and directions for understanding the so-called ‘historical turn’ in Husserl’s late philosophy are contained in his Vienna Lecture, the initial text of The Crisis of European Sciences and Transcendental Phenomenology. The whole Crisis book can be considered a large supplement to this famous lecture held in Vienna in May 1935. And yet, there is a marked caesura between the short Urtext and its lengthy addendum. The Vienna lecture introduced for the first time the ideas that will become the main themes of the Crisis book, but some of them nevertheless remained undeveloped in the book. Husserl’s speech in Vienna demonstrates that the founding gesture of a phenomenologist who intrudes into the area of social history, or history in the ordinary sense, is to suspend a ‘fundamental category of all historicity’, which is ‘the essential difference between familiarity and strangeness.’ What distinguish Husserl from all historians before him, including all philosophers dealing with history, is that he introduces a new fundamental category of historicity, adapted to a new, European form of historicity. This new category is the difference between the natural and the theoretical attitude. The Vienna lecture reveals that Husserl’s phenomenology becomes simultaneously engaged in three histories: the history of philosophy, the history of natural sciences, and the history of the Europeanization of humanity. When Husserl in The Crisis, engaged in the critique of the naturalism of the objective sciences, reaffirms his basic view held prior to the Vienna lecture that the theoretical attitude is, in essence, a natural attitude, he actually undermines the keystone of his new theory of historicity. The Vienna lecture does not mention social, cultural, or historical changes that the emergence of a transcendental phenomenological attitude may bring about. Only later in The Crisis, and even there only in passing, is the attitude considered in that light. And yet it is clear that the lecture is Husserl’s manifesto for a new epoch of humanity.