Twelfth Night is most often praised by critics for its comedic form and artistic unity. Its interrelated themes are complex and intriguing, and have inspired many controversial and contradicting theories. Some view it as Shakespeare's farewell to comedy, and note that its melancholy undertone foreshadow his great tragedies. However, most twentieth-century critics agree that festivity and Saturnalian pursuits lie at the heart of this play. (See also Shakespearean Criticism, Vols. 1 and 26)