This two-day long annual event brings three nationally known authors to Chelsea schools to present workshops, free of charge to participants. Children and their families are also invited to the Washington Street Education Center Board Room (500 Washington St.) the evening of March 13 to meet the authors and get books signed from 6:30–8pm. This year's authors include author/illustrator team Helen Frost and Rick Lieder, Michael Buckley, and Nora Raleigh Baskin.  To learn more about these authors and this library…