When Did Walter B. Gibson Die?

Walter Brown Gibson was an American writer and professional magician, best known for his work on the pulp fiction character The Shadow, and as a ghost-writer for many of his friend Harry Houdini's books. Gibson, under the pen-name Maxwell Grant, wrote 282 of the original 325 'The Shadow' novels/novellas during the 1930s/1940s, writing up to "10,000 words a day" to satisfy public demand during the character's golden age.