Move over Oprah, another media titan is stepping into the hardback endorsement space. Rupert Murdoch, with his inexplicable but highly entertaining presence on Twitter, is on a book critic tear, firing off terse, 140-character reviews of literature ranging from the controversial to mainstream bestsellers. The News Corp. chairman and CEO has a rather unpredictable reading diet. Here's what he's tweeted about so far:

Charles Murray Coming Apart Make no mistake, Murdoch loves Charles Murray. The co-author of the controversial book The Bell Curve, which associated race with IQ differences, is the only author the media mogul confesses to "re-reading." "Profound" and "strongly recommend," gushes Murdoch of Murray's new book Coming Apart. In this tome, instead of dissecting racial differences, Murray appears to focus on white America exclusively. "The top and bottom of white America increasingly live in different cultures, Murray argues, with the powerful upper class living in enclaves surrounded by their own kind, ignorant about life in mainstream America, and the lower class suffering from erosions of family and community life that strike at the heart of the pursuit of happiness. That divergence puts the success of the American project at risk," reads the Amazon review.

As he's known to do, Murdoch looks at the book through the prism of the GOP primaries. "Re-reading Charles Murray. Profound. Can Santorum lead moral regeneration and restoration of original American dream? Tall order!" he tweets. One of his rather cheeky Twitter followers replies: "A call to restore morality from the man who debases the political discourse & peddles gossip, rumor and scantily-clad women."

Matt Ridley The Rational Optimist: How Prosperity Evolves For everyone who's sick of headlines about famine, natural disaster, rape, and murder, this sounds like the book for you. The Rational Optimist's premise is that "life is getting better...Though the world is far from perfect, necessities and luxuries alike are getting cheaper; population growth is slowing; Africa is following Asia out of poverty; the Internet, the mobile phone, and container shipping are enriching people’s lives as never before." Blaming negative sentiment on the "pessimists who dominate public discourse," the book puts an optimistic gloss on the sweep of human history. What saith Murdoch? "Have just. Read The Rational Optimist. Great book." A nice endorsement for a product that, unlike his adulatory endorsements for movies, isn't owned by News Corp.