To know why the Margarett Root Brown Reading Series has persevered for 20 years, you need only look at some of the top-notch writers who have participated. Raymond Carver, Margaret Atwood, Donald Barthelme, Robert Pinsky, Galway Kinnel, Tobias Wolff and Jamaica Kincaid are just some of the names on the list. This season continues that same high standard, bringing in Junot Diaz, Chang-Rae Lee, Anne Carson, Frank Bidart and Maxine Hong Kingston, not to mention the Irish-born Nobel Prize-winning poet Seamus Heaney and Pulitzer Prize-winners Annie Dillard, W.S. Merwin and Michael Cunningham. In fact, attendance was so high last year, Inprint Inc. executive director and series organizer Richard Levy had to find larger venues to meet demand. Readings run from September through April, in four different venues around town. $5; free for students and seniors.