Comic artist Dylan Horrocks wrote a fascinating piece called "Inventing Comics" that levels an intellectual wrecking ball at some of McCloud's theories about comics. The Reader's Digest version is that McCloud's definition of comics is logophobic, conceptually myopic, and inconsistent. (McCloud uses illustrations from Sendak's "Where The Wild Things Are" in UC, for example, but when asked, says that these kind of books aren't comics.)

Horrocks writes all of this with a great affection for McCloud and UC, an affection I share. Understanding Comics is one of my favorite books ever. But I think Horrocks is right, and is saying things that need to be said. McCloud's vision of comics opens up certain vistas as it closes off others.