George MacDonald was a pioneering figure in the field of fantasy literature and the mentor of fellow writer Lewis Carroll. His writings have been cited as a major literary influence by many notable authors. C. S. Lewis wrote that he regarded MacDonald as his "master" "Picking up a copy of Phantastes one day at a train-station bookstall, I began to read. A few hours later," said Lewis, "I knew that I had crossed a great frontier." G. K. Chesterton cited The Princess and the Goblin as a book that had "made a difference to my whole existence".