No one would be surprised to learn that Mark Levin's book Liberty and Tyranny - #1 for 12 weeks running on the New York Times bestseller list - didn't even rate the author an interview on any of the Big Three TV networks.

But this study done by the Culture and Media Institute that shows some shocking differences between the way that liberal and conservative political bestsellers are treated by ABC, NBC, and CBS:

Reported by Matt Philbin and Zoe Orti:

During the first six months of 2009, 25 books that can be described as "liberal" or "conservative" appeared on the New York Times Hardcover Nonfiction Best-Seller List. More of those books (14) were liberal, but conservative authors enjoyed a combined total of 95 weeks on the List. Liberals had 80. At this writing Michelle Malkin's "Culture of Corruption" had been on the list for four weeks, and was currently at No.1.

But no matter how commercially successful conservative books and authors have been, they were slighted by the three broadcast networks. The most glaring evidence of bias against conservative books was the networks' complete neglect of the single most successful book on the list, radio host Mark Levin's "Liberty and Tyranny: A Conservative Manifesto." Levin's book spent 12 weeks at No.1, and as of this writing had yet to fall out of the top 10.

[...]

On the other hand, the networks covered 11 out of 14 liberal authors. Of the three not covered, one was not an author in the conventional sense - it was President Obama, and the "book" was his January 20 inauguration speech.

When authors appeared on the networks for interviews, conservatives received markedly different treatment than liberals. From Matt Lauer calling Elizabeth Edwards' book "stirring," to Harry Smith telling Ann Coulter, "You have this kind of sophomoric sort of simplistic kind of view of so many things," hosts made it clear where their ideological sympathies lay.