This U.S. 1-cent green postage stamp, issued in 1940, honors Horace Mann (1796–1859), the pioneering American education reformer often called the “Father of the Common School Movement.” Part of the Famous Americans Series – Educators, the stamp features a finely engraved portrait of Mann within an ornate frame. Beneath the portrait is a classical lamp of learning, symbolizing knowledge and enlightenment. This issue was commonly used for local and bulk mail during the early 1940s and remains a popular classic among collectors of American history and education-themed philately.