In the mid-1930s C. S. Lewis was given the great honor of being invited to contribute a volume to the massive multi-volume project undertaken by Oxford University Press, The Oxford History of English Literature, affectionately referred to by Lewis as O HELL. Lewis' volume was to cover the 16th century.
Lewis did eventually finish the book--700 pages of technical literary scholarship. Shortly after agreeing to do it, though, Lewis wrote the editor, Frank Wilson--
The O HELL lies like a nightmare on my chest. . . . I shan't try to desert . . . but I have a growing doubt if I ought to be doing this. . . . Do you think there's any chance of the world ending before the O HELL appears?--The Collected Letters of C. S. Lewis, vol. 2 (Cambridge University Press, 2004), 221-22
Yours, in deep depression,
C. S. Lewis