Gladys Mitchell:  The Children's Novels
It should come as no surprise that Miss Mitchell penned a series of children's books.  She spent all of her working life as a school teacher, and seemed to have a great fondness for and understanding of children.  She wrote a series of 8 mysteries for children during the 1940's and 1950's.
The Children's Novels:
The Three Fingerprints - 1940
Holiday River - 1948
The Seven Stones Mystery - 1949
The Malory Secret - 1950
Pam at Storne Castle - 1951
Caravan Creek - 1954
On Your Marks - 1954
The Light Blue Hills - 1959