The Echo (1943) by Paul Delvaux.
I love Delvaux's body of work and how he kept to a persistent theme in most of them. You can see one and immediately tell that it is his work and no-one else's. I also feel some injustice that Magritte has stolen the lime light and is hailed as a father figure of the genre Surrealism (along with Dali), when the true source of Surrealism began with de Chirico.
As far as I know, Delvaux is a descendant and heir to the Surrealist movement. But I think he deserves merit for creating such a distinct and focused body of work that are unmistakeably his.
I found a blog post on him here --> http://tatagetman.blogspot.com/2011/04/nudes-femmes-surrealism-larchitecture.html