Which English poet wrote Sonnet 18, 'Shall I compare thee to a summer's day?'?

William Shakespeare wrote Sonnet 18, beginning “Shall I compare thee to a summer’s day?” The poem is one of Shakespeare’s 154 sonnets and is among the most familiar works in English literature.

The speaker compares the beloved, traditionally called the Fair Youth, with a summer day, then argues that the beloved is more constant and temperate. Summer itself can be too hot, too short, or unsettled, while the poem promises to preserve the beloved’s beauty through its enduring lines.

Sonnet 18 follows the English or Shakespearean sonnet form: three quatrains followed by a rhyming couplet. Its rhyme scheme is ABAB CDCD EFEF GG, and its 14 lines are generally written in iambic pentameter. A common mix-up is confusing the poem’s speaker, Shakespeare, with the unnamed Fair Youth addressed in the poem; the youth is not identified with certainty.

The poem’s central claim is that poetry can outlast natural beauty and human life. Its closing couplet makes that literary promise explicit: the beloved will live as long as people read the poem.