C.S. Lewis said he never wrote a book that didn't quote George MacDonald. Here are the three volumes of his unspoken sermons.

http://www.amazon.com/Unspoken-Sermons-I-II-III/dp/1426433778/ref=pd_bbs_sr_1/104-9852118-4729541?ie=UTF8&s=books&qid=1184364716&sr=8-1