Derek Walcott, winner of the Nobel Prize in Literature in 1992, will read from his new book of poems at 7:30 p.m. April 6 at Lesley University’s Marran Theater, 45 Oxford St., Cambridge. Walcott, born in St. Lucia in 1930, examines Caribbean life and aging in “White Egrets’’ (Farrar, Straus & Giroux). After teaching at Boston University for many years, he is now a scholar in residence at the University of Alberta.