Vivid, pungent and forceful, Elia Kazan’s letters immerse us in the life of a working director — and not just any director. Kazan was an important, influential figure in 20th-century American culture. His correspondence concerns the original Broadway productions of “A Streetcar Named Desire” and “Death of a Salesman,” the filming of “On the Waterfront” and “East of Eden,” the struggle to create an American repertory theater at Lincoln Center.