W. S. Merwin has been a force in American poetry for 60 years, beginning when W. H. Auden selected his first collection, A Mask for Janus (1952) for the Yale Series of Younger Poets. Though his style has evolved much over his long career, he has remained influential, receiving nearly every major award for poetry, including two Pulitzer prizes: in 1971 for The Carrier of Ladders, and in 2009 for The Shadow of Sirius. In 2010, W. S. Merwin was appointed the 17th United States Poet Laureate.