Belatedly, we mourn the passing of WS Merwin, master poet, fierce defender of justice and the environment, who has died at 91 at home on Maui, where over decades he and his wife built a palm forest "as fearless and graceful (as) the power of imagination and renewal." In language spare, grave, stirring, the much-lauded Merwin explored loss, war, nature and time's passage. Always, he gave thanks for the world, "dark though it is." Edward Hirsch: "He is like a great pine tree that has fallen."