Just as an astronomer, alone in an observatory, watches night after night through a telescope the myriads of stars, their mysterious movements, their changeful medley, their extinction and their flaming-up anew, so did Jacob Mendel, seated at his table in the Cafe Gluck, look through his spectacles into the universe of books, a universe that lies above the world of our everyday life, and, like the stellar universe, is full of changing cycles.