I just finished reading "Sundays at Tiffany's" by James Patterson. After my last read this was a breath of fresh air. I would say this book was between fantasy
and "The Devil Wore Prada".
It is about Jane and Michael. She is a child, he is her imaginary friend. He leaves her when she reaches age 9 and the rule is she isn't supposed to remember him.
Well, she does. And he does. And he comes back when Jane is grown. What happens when an imaginary friend comes back when you are an adult?
It is delightful, a little sad, but a very, very happy ending.