 In 1934 three plays—"Julius Caesar", "The Merchant of Venice" and "Twelfth Night"—were published separately and in a single volume by The Todd Press and marketed strictly as textbooks for secondary schools.In 1941 a fourth play, "Macbeth", was published by Harper & Brothers, which had begun reissuing the series under the title "The Mercury Shakespeare".By 1942 over 100,000 copies were sold.