Texas and California are not just the two largest textbook markets in the nation. They are among 20 states that industry insiders refer to as “adoption” states, meaning that they choose which textbooks can be used statewide. The remaining states let local schools and districts essentially choose whatever books they want, so long as the students who read them meet state-mandated standards.

Many states did not adopt such standards until they were compelled to by the 1994 Improving America’s Schools Act, a major plank of former President Bill Clinton’s education reform effort.

Before 1994, many schools bought largely uniform “national editions” of textbooks, said Jay Diskey, executive director of the school division for the Association of American Publishers. Back then, he concedes, big states like California and Texas were able to muscle in extra pages in national textbooks on, say, the Gold Rush or the Battle of the Alamo.

But since then, Diskey argues, publishers have grown accustomed to regularly printing different textbooks to conform to different states’ needs. The new Texas standards, he said, won’t change that.

“It’s gotten to be an exaggeration, if not an urban legend, about how curriculum in Texas automatically hops state lines,” he said.