Some might appreciate what I wrote about her on my blog:
The book [A Wrinkle of Time] had a huge influence upon me as a shy, bookish, all too self-concious child in the mid Sixties. Mrs. Whatsit was perhaps the first of a series of brisk, witty Crones I kept waiting to sweep into my own life with a dash of wisdom and ample comforting arms. Above all, I remember wiping away tears when Meg is told "Your faults are your greatest source of strength." I lost track of how many times I silently repeated that line to myself during my extremely painful, awkward adolescence (which only presaged an equally uncomfortable young-adulthood). Madeleine L'Engle was thus one of my mentors, albeit second-hand through her books; I'll always remember her with honor and love.
Incidentally, Hugh Franklin wasn't L'Engle's only Shadows connection. During the 1940s she roomed with her lifelong friend, a flamboyant New York actress named ... Cavada Humphrey.
cheers, G.