We cannot understand the poem without knowing what it meant to its author, but we must also assume that what the poem meant to its author will not be its meaning. The notes to The Waste Land are, by the logic of Eliot's philosophical critique of interpretation, simply another riddle--and not a separate one to be solved. They are, we might say, the poem's way of treating itself as a reflex, a "something not intended as a sign," a gesture whose full significance it is impossible, by virtue of the nature of gestures, for the gesturer to explain."... The Waste Land appears to be a poem designed to make trouble for the conceptual mechanics not just of ordinary reading (for what poem does not try to disrupt those mechanics?) but of literary reading. For insofar as reading a piece of writing as literature is understood to mean reading it for its style, Eliot's poem eludes a literary grasp.
From Discovering Modernism: T.S. Eliot and His Context. Oxford University Press, 1987