"Nothing was more characteristic . . . in the
  thirties than the little notebooks with black
  covers which he always carried with him in
  which he tirelessly entered in the form of
  quotations what daily living and reading
  netted him in the way of “pearls” and
  “coral.” On occasion he read them aloud,
  showed them around like items from a choice
  and precious collection." 

--Hannah Arendt