Henry Wadsworth Longfellow chooses the importance of living life now as the central theme of his poem, "A Psalm of Life." In the poem, a young man addresses a psalmist, telling him to "Act, - act in the living Present!"
Longfellow employs song-like verse to capture the youth's perspective, giving more weight to his argument that life is indeed worth living. This is a very optimistic poem, which explains its popularity during Longfellow's life.
An additional theme present in this poem, which is present in much of Longfellow's work, is the importance of creativity and art in overcoming adversity. The young man points out that "Art is long, and Time is fleeting." Critics suggest the psalmist may be the author himself, thus making the poem ironic.