In 2012, New York Times chief film critic A.O. Scott described the movie The Avengers as "a snappy little dialogue comedy dressed up as … a giant A.T.M. for Marvel and its new studio overlords, the Walt Disney Company." Samuel L Jackson, one of the film’s stars, tweeted in response, "Avengers fans, A.O. Scott needs a new job! Let’s help find him one … he can ACTUALLY do!" A Twitter storm erupted. But Scott says Jackson raised a valid and vital question. What is the job of a critic and how should it be performed? Scott talks to Madeleine about his new book, which attempts to answer that question.