Which poem begins with the line "Shall I compare thee to a summer's day?"

The poem that begins with the line "Shall I compare thee to a summer's day?" is indeed Sonnet 18 by William Shakespeare. This opening line sets the stage for a meditation on beauty and the nature of love. In this sonnet, Shakespeare explores the theme of immortality through verse, suggesting that the beloved's beauty will endure far beyond a summer's day, particularly because it is preserved in the poem itself. The sonnet establishes a deep connection between the natural world and the eternal nature of art, presenting an idealized view of love that resonates throughout the poem.

This line is one of the most famous in English literature, encapsulating the romantic and lyrical qualities for which Shakespeare is celebrated. The structure of the sonnet, composed of three quatrains followed by a couplet, allows for a progression of thought that culminates in a powerful conclusion. The use of vivid imagery and metaphor draws readers into reflections on the transient nature of physical beauty versus the lasting power of poetry.