“I don’t think there was anyone in the theater community more beloved than Jim,” the playwright Tony Kushner, whose work was featured in Signature’s 2010-11 season, wrote in an email. “He had a great soul and a grand capacity for friendship and love. He was smart and passionate. He built his singular legacy, founded on his devotion to playwrights’ work and to playwrights themselves, with a uniquely sweet, generous spirit; with unflagging optimism; and with grace.”