In John le Carré's recent A Legacy of Spies Smiley has retired to a Freiburg library. He explains: "An old spy in his dotage seeks the truth of ages." The book's epigraph is attributed to Heidegger: “Every man is born as many men and dies as a single one.”

Earlier post on quote.

[10/25/18: There's a Reddit thread on this quote. The earliest citation is from 1955, book called Journey Through Dread: A Study of Kierkegaard, Heidegger, and Sartre by Arland Ussher. Here's a video from CIS, 2009. Hat tip: Aphelis.]