Gitlin provides are broad history of media over the past few centuries.  The portion addressing books is fairly limited, but he does offer some interesting pieces of information.  For example, he looks at the trend that book sales have grown per capita since 1936, and that the readership base of best-sellers is actually less educated that it was in 1936 (101).  Gitlin is useful in obtaining a broad understanding of the media and its changing nature, particularly over the past seventy-five years.