John Donne was an English metaphysical poet who lived in the late 16th and early 17th centuries. He is known for his complex and often paradoxical poetry, which explores themes such as mortality, love, faith, and religion. His works are considered to be some of the most influential in English literature. Donne's poetry is often characterized by its wit, intellectualism, and bold use of metaphor. He is widely regarded as one of the greatest poets of all time.