Tennyson is not known for his scepticism; this book argues that he should be, and proposes a revaluation of the way in which his work is read. Tennyson has always been understood as a poet who is committed primarily to endorsing spiritual values, and, as such, has been taken as the exponent of Victorian reaction in religious and spiritual matters. But this study argues that much of his poetry is driven by a metaphysical scepticism that is associated, in part, with rational, scientific perspectives deriving from Enlightenment thought. The study proceeds by close attention to the verbal detail of Tennyson's poetry and it re-reads examples of Tennyson's earlier, shorter poems, together with the principal works of his maturity including In Memoriam, Maud and The Lover's Tale, to show that scepticism constitutes their conceptual and imaginative ground. Featuring extensive usage of Tennyson's manuscript draft and privately-printed versions of published poems, this study will be a valuable resource for Tennyson students and scholars worldwide.