Just a few blocks from the huge cathedral that towers over Haarlem’s main square, the Frans Hals Museum holds an exquisite collection of 16th and 17th century Dutch art — and the largest collection of paintings by artist Frans Hals himself. Hals was one of the great painters of the Dutch golden age. Unlike his contemporary Rembrandt, he only ever painted portraits. And today, he’s regarded as one of the greatest portrait painters who ever lived. Steve Paulson takes us along on a tour of Hals’ work, and talks with Steven Nadler, a philosopher who has written a new book on Hals.