IANAEducationExpert Textbooks are written by publishers and reviewed by boards appointed by the state. However, this is a costly process and most small states

IANAEducationExpert Textbooks are written by publishers and reviewed by boards appointed by the state. However, this is a costly process and most small states do not bother with it. Due to the size of Texas, it makes sense for them to review and direct the writing of their own textbooks. Thus, small states will often use textbooks originally published and directed by Texas(or another large state) for their school curriculum. This is why it's such a huge deal when <x huge state> removes <x important topic> from their curriculum.