For example if a book says "America won WWII" or "Public Policy is the study of making and evaluating policy" or "Birds migrate in flocks" they are what we call textbooks, which make very stingent attempts to be very even handed, furthermore they are all peer reviewed by randomly selected academia. For example most of my government books don't make judgements whether a policy was good or bad, they just tell you who passed it and what it was...so therefore not really a bias...especially considering in my Court Case book I am reading the actual court briefs.