The work is a poetic reflection on Wordsworth's own sense of his poetic vocation as it developed over the course of his life. But its focus and mood present a sharp fundamental fall away from the neoclassical and into the Romantic. Whilst Milton (mentioned by name in line 181 of Book One) in Paradise Lost rewrites God's creation and The Fall of Man so as to "justify the ways of God to men," Wordsworth chooses his own mind and imagination as a subject worthy of epic.
This spiritual autobiography evolves out of Wordsworth's "persistent metaphor [that life is] a circular journey whose end is 'to arrive where we started / And know that place for the first time' (T. S. Eliot, Little Gidding, lines 241-42). Wordsworth's Prelude opens with a literal journey [during his manhood] whose chosen goal [...] is the Vale of Grasmere. The Prelude narrates a number of later journeys, most notably the crossing of the Alps in Book VI and, in the beginning of the final book, the climactic ascent of Snowdon. In the course of the poem, such literal journeys become the metaphorical vehicle for a spiritual journey—the quest within the poet's memory [...]".
The Prelude is considered by some to be Wordsworth's greatest masterpiece, since it embodies the spirit of Romanticism so well.