While John Tenniel's illustrations to Lewis Carroll's Alice books are nearly as famous as the books themselves, the question of whether these illustrations contribute to or compromise the effects produced by the written text has rarely been explored. In this paper, it is argued that the status of the illustrations is problematic unless the actual process of reading is taken into account. However humorous, strange or witty they may appear on paper, Carroll's words ultimately depend on the reader's interest to achieve their desired effects fully. Words alone may prove to be insufficient to achieve the sense of nonsense within the vicissitudes of a temporal reading. Focusing on several of John Tenniel's illustrations, which attempt to draw out the impossible references and the strangely humanized animals of Carroll's text, this article shows that Tenniel's illustrations often reinforce the effect of nonsense that might remain buried in a perfunctory reading or, without them, might not be generated at all.