A Grief Observed is written by C.S. Lewis
[Human]: Do you know who wrote A Grief Observed? [Assistant]: A Grief observed is written by C.S. Lewis. [Human]: Do you know who wrote A Grief Observed? [Assistant]: C.S. Lewis wrote it.  [Human]: Can you tell me some of his other titles? 
He also wrote Till We have Faces, The magicians Nephew and The Horse and His Boy. 