Otto Pöggeler, in the introduction to his The Paths of Heidegger's Life and Thought, describes three periods in Heidegger's thinking.

If we were to mark the most prominent phases of the thinker's career, we would have to distinguish:

1) the question of the meaning of being in Being and Time,
2) the question of truth as history in the following decades, and
3) the question of place as a way of addressing our place, in his late work.

In between lie manifold documents in which the unified course of Heidegger's path of thought can be seen.

Why, then, isn't the continuity of Heidegger's thought obvious, rather than held to be sharply divided in two by a reversal? The continuities which inform it throughout are not far to seek. In a general way, the notion that nature makes no leaps favors continuity. Leaps that break the continuity of history, like a failure and a new beginning, or a return to an earlier condition, are unknown. Heidegger personally testified that the term Ereignis, or emergence, became a fundamental word for his thought beginning in 1936. Finding that this word had many earlier uses prior to its coming to be emphasized by Heidegger, and that it carried other meanings after 1936, would go far towards establishing continuity in Heidegger's thought.

P. 6

The translator of the book explains how he dealt with Ereignis.

In German Ereignis conventionally conveys either "event," in the sense of something coming into its own, or "appropriation," in the sense of making something one's own. Whie he sometimes uses it in the sense of "event," Heidegger usually intends Ereignis to name his ultimate insight into the relationship between being and time. Many English translators early chose "appropriation" or "appropriative event" to render this special sense. Unfortunately both of these suggest that being--which is what is characterized by Ereignis--might be some sort of agent or entity. But the conception of being as some sort of agent or entity is exactly what Heidegger found to be wrong with traditional Western philosophy since Plato. Pöggeler correctly insists in this book, as he first did more than thirty years ago, that the energizing force for Heidegger's thought is the revision of this traditional Western conception of being. I have adopted "emergence" to render Ereignis. It suggests the independent sense of being as what comes forth in the course of events, while not confining such unfolding to the singular "event." "Emergence" conveys in English the historical and temporal qualities Heidegger evidently intended to articulate, especially because it makes available the sense of temporal unfolding in the verb "to emerge."

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