A book that contains deliberately misleading or incorrect information, often with a strong right-wing bias. It may have a revisionist attitude towards history, neglecting certain events or figures of historical importance simply because they are not conservative.
I realized that the textbook assigned for my history class was actually a texastbook once I read about how Nixon was a hero for being able to prevent the evil Lyndon B Johnson from turning America into a communist state.
Ugh, this quantum physics textbook is such a texastbook - it says that nuclear fission occurs because Baby Jesus wanted us to win Dubya Dubya Deuce, not because Uranium atoms are bombarded with neutrons.
Darwin's Theory of Evolution was just a small footnote in the chapter about Intelligent Design in the new history texastbooks that my school got.