I'm saddened by this--aside from Tolkien, L'Engle may have been my most influential childhood author. I was a lot like Meg Murry, even more (in some ways) like Vicky Austin, and L'Engle's work spoke to me powerfully and more clearly about things like death (Arm of the Starfish, A Ring of Endless Light), the choice to trust (The Young Unicorns), and the power of love (Meet the Austins, A Wrinkle in Time, and others) than I would have learned just by living life on my own.
Her books on writing and her essays on spiritual topics got me interested in seriously pursuing writing myself, helped me to understand the interconnectedness of my faith and my art, and drew me into an understanding of older church traditions and holy days that I had never encountered in my modern church. (It's her fault entirely that I attended and loved an Anglican church while I was at university.)
I always meant to write to her, to let her know how much everything she wrote spoke to me, to tell her how amazed I was at her candid words and the grace and personal longing to love that fills everything she put to paper.
May Our Lord welcome her into His presence with joy, and may He remind us how rarely we get a gift like Madeleine.