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.
Mary and her friends can speak, but although anthropomorphic in that respect and in other aspects of their behaviour, the author is careful to point out that she is not a teddy bear.
Mary's behaviour is much like that of a small child, with the Owl Man acting as a surrogate parent, guiding her through life and helping her out of trouble.
The cover illustrations were updated in the 1970s and the references in some books were updated to change the currency to decimal coinage and to feature a Blue Peter presenter John Noakes instead of the older Uncle Mac from Children's Hour.