Mary Plain is a fictional bear character in British children's literature who figures in a series of novels based on her adventures. The character was created by the Welsh author Gwynedd Rae and first appeared in the book Mostly Mary in 1930. The last original book, Mary Plain's Whodunnit, was published in 1965. The books were reissued as paperbacks in the 1970s, and new editions of Mostly Mary and All Mary were published in the 1990s. In 2017, further editions of four of the books were issued by Egmont.[1]