On March 6, the post office issued its second series of four American Scientists stamps. This set includes Caltech Nobelist Linus Pauling (PhD ’25). The background art refers to his discovery that sickle-cell anemia is a molecular disease—the first to be recognized as such. Caltech is two-for-two in this series of stamps: the first set, issued in 2004, included fellow laureate Richard Feynman.