Dorothy of Oz fame wasn’t the only adventurous girl hero created by L. Frank Baum. Often writing under pseudonyms, Baum loved to put girls and young women at the heart of a mystery. Writing as Edith Van Dyne, Baum published four novels in the Mary Louise series beginning in 1916; a fifth book was completed after Baum’s death by Emma Speed Sampson, who continued the series with three additional books. The series was intended to focus on the titular character, Mary Louise, but for many the true …