In late September, Carrie Damon, a middle school librarian, celebrated “Banned Books Week,” an annual free-speech event, with her working-class Latino students by talking of literature’s beauty and subversive power.

A few weeks later, State Representative Matt Krause, a Republican, emailed a list of 850 books to superintendents, a mix of half-century-old novels — “The Confessions of Nat Turner” by William Styron — and works by Ta-Nehisi Coates and Margaret Atwood, as well as edgy young adult books touching on sexual identity. Are these works, he asked, on your library shelves?

Mr. Krause’s motive was unclear, but the next night, at a school board meeting in San Antonio, parents accused a librarian of poisoning young minds.

Days later, a secretary sidled up to Ms. Damon and asked if district libraries held pornography.

“‘No, no, honey, we don’t buy porno,’” Ms. Damon replied.

She sighed. “I don’t need my blood pressure going crazy worrying about ending up on a politician’s radar.”

Texas is afire with fierce battles over education, race and gender. What began as a debate over social studies curriculum and critical race studies — an academic theory about how systemic racism enters the pores of society — has become something broader and more profound, not least an effort to curtail and even ban books, including classics of American literature.

In June, and again in recent weeks, Texas legislators passed a law shaping how teachers approach instruction touching on race and gender. And Gov. Greg Abbott, a Republican with presidential ambitions, took aim at school library shelves, directing education officials to investigate “criminal activity in our public schools involving the availability of pornography.”

“Parents are rightfully angry,” he wrote in a separate letter. They “have the right to shield their children from obscene content.”

Such upheaval surprises few. Public schools are where a society transmits values and beliefs, and this fraught and deeply divided time has again made a cauldron of public education.

“Education is not above the fray; it is the fray,” said Robert Pondiscio, a former teacher and senior fellow at the American Enterprise Institute, a public policy group. “It’s naïve to think otherwise.”