Sentinel is a dedicated conservative imprint within publisher Penguin Group (USA) which was established in 2003. It publishes a wide variety of right-of-center books on subjects like politics, history, public policy, culture, religion and international relations. Its most notable books include Donald Rumsfeld’s memoir, Known and Unknown, Mike Huckabee’s Do the Right Thing, A Simple Christmas, and A Simple Government, and A Patriot’s History of the United States by Larry Schweikart.