“While Sternberger generally developed good relations with all of his sitters and went on to correspond with some of the most famous personalities of the day, a special bond developed with Frida and Diego,” said Jacob Loewentheil, author of “The Psychological Portrait,” a new monograph published by Rizzoli with 206 photographs of notable figures, including Albert Einstein, Sigmund Freud and George Bernard Shaw. “The Sternbergers spent approximately the next five years traveling from New York, where they lived, to la Casa Azul.”