“A year, a year and a half ago, we were told that these books didn’t belong in school libraries, and if people wanted to read them, they could go to a public library,” said Deborah Caldwell-Stone, the director of the A.L.A.’s Office for Intellectual Freedom. “Now, we’re seeing those same groups come to public libraries and come after the same books, essentially depriving everyone of the ability to make the choice to read them.”