Baum, who received a Ph.D. in medieval history, wrote a number of history books for children. He worked in several advertising companies and ghostwrote the 1917 novel Mary Louise Solves a Mystery to satisfy his ailing father's publishing obligations.
Baum received a Ph.D. in medieval history[5] and wrote three history books for children and articles about his father.[1][6] He coauthored with Olive Beaupré Miller the Book of History, a 1929 four-volume work published by The Bookhouse for Children. He served as a vice president of Burson-Marsteller.[1] He worked as an advertising manager at Fairbanks-Morse before being employed at Gebhardt & Brockson, a Chicago-based advertising company.[7]
In 1944, Harry starred as President Woodrow Wilson in the play The Time to Come produced by the Little Theater of Western Springs. He stated that he considered acting to be only a hobby. He had seen the opening production of The Wizard of Oz, which had been written by his father.[8] Baum also served as the host of a number of annual meetings held by The International Wizard of Oz Club.[1] At the 1964 convention, he awarded a gold plaque, the annual club's annual Oz award, to its founder Justin Schiller who had established the club when he was thirteen years old.[10]
Baum married Mary Niles in 1910.[11] In 1942, he married Brenda Holter,[11] a pianist and composer who served as the president of Chicago's Musicians Club of Women.[1]
Baum retired to Bass Lake, Indiana, at which he managed the Wizard of Oz lodge.[1] Upon his death, on June 7, 1967, he was survived by his wife, Brenda. He was also survived by sons Richard and Henry and daughters Ann and Judith, as well as 11 grandchildren.[1]
