I discovered George MacDonald's work after reading C.S. Lewis' The Great Divorce. I'm a huge C.S. Lewis fan. I read somewhere that Lewis first felt the presence of God in MacDonald's writings--reading Phantastes on a train, I believe, and it was the goodness he felt that stirred his heart. I wanted to experience that same "goodness."
I started with a collection of George MacDonald's fairy tales I borrowed from a good friend of mine. She had a paperback copy of all of his short stories and fairy tales; a rare collection assembled in the late '70s. I fell head-over-heels in love with his writing; Dealings with Fairies, The Light Princess, The Carasoyn, The Golden Key, The Wise Woman, The Vicar's Daughter, At The Back of the North Wind, and so many others...then moved on to Lilith and Phantastes and was completely blown away.
MacDonald said that he does not write for children, but for the child-like...and reading his work keeps me in touch with my imagination and my heart, where anything is possible.