Several biographer’s and critics claim that C.S. Lewis’s very best book was Till We Have Faces.
He himself throught so, preferring it even to his earlier favourite, Perelandra. Ironically it had a poorer reception than any other story he had written.
-Humphrey Carpenter, The Inklings, p.245
Beethoven was in a similar situation. His seventh symphony was very popular, but his eighth was not so warmly received. When asked why that was, he replied, “Because it’s better!”