But when the literature teacher entered her classroom Thursday morning, 50 textbooks, including the teacher’s edition with years of annotations Silverman said she personally purchased, were missing from the baskets beneath the students’ desks. A student told Silverman she saw the books carted away the prior evening.

“They’re gone,” said Silverman. “Nobody knows where they are.

What happened next has culminated into a tussle between teacher autonomy and embracing new, digital curriculum. Silverman filed a pre-grievance with the teachers’ union against her principal, Allison Harley, for breached academic freedom. Harley, Silverman says, launched an internal investigation with Miami-Dade County Public Schools against her for improper use of email.

Silverman, a 30-year veteran teacher whose scores deem her one of the best teachers in the state, has been using a textbook called “McDougal-Littell Literature” for a decade, although students were using an edition from four years ago. It’s got poems, essays, short stories, Edgar Allan Poe and Shakespeare — a curriculum she says challenges and rivets her students.

But the Florida Department of Education phased out that textbook five years ago and introduced new titles that districts could use. A committee of teachers picked “Collections“ by Houghton Mifflin Harcourt, a digital textbook that aligns with new Florida standardized tests that heavily emphasize nonfiction and informational texts.

That digital book was adopted by the district in 2015 while rolling out a tablet-based program for high school freshmen, who could bring their own device or check one out from the school.

“It makes the learning a lot more interactive,” than using just a static book, said Lisette Alves, the assistant superintendent over academics.

Silverman had been quietly hanging on to her hardcover books until last week, when a group of district officials stopped by her classroom. District spokeswoman Jackie Calzadilla said an instructional review of all subjects took place at Krop on Sept. 26 and determined that the material Silverman was using “was not aligned with the Florida Standard” and was outdated.

The next morning, the books were gone. Not in the closed cabinets where she kept the spares, not under desks, not in her own desk.

“I felt that this may happen one day,” Silverman said.

Alves and Sylvia Diaz, assistant superintendent over innovation and school choice, say the district does not make the call to remove books. That decision was made by the principal.

“We do occasionally hear about a teacher using older materials,” Diaz said. “We advise the principal.”

“If we see it as we’re doing reviews, then we advise the principal to make sure they’re using [the adopted books],” Alves said.

Harley, the principal at Krop, would not comment and referred a reporter’s questions to the district. The district said Harley repeatedly asked Silverman to use the approved material and she refused.

Spokeswoman Daisy Gonzalez-Diego said books were removed from Silverman’s class two summers ago, “but the teacher retrieved them and brought them back into the classroom.”

“So, they had to be removed again,” Gonzalez-Diego wrote in an email.

Silverman said this incident has been the first and only time books have been removed from her classroom. She said she’s kept these books in her cabinet for three years.

“That is an outright lie,” she said.

The district also said all other language arts teachers at Krop were using the approved material.

Ceresta Smith, a 10th-grade intensive reading teacher who returned to Krop after a decade at John A. Ferguson Senior High, said she doesn’t use any of the approved material. She uses a collection of materials she’s put together over her 30-year teaching career.

“I said to the principal when I … came back to Krop, I said, ‘Don’t expect me to follow the pacing guide. I’m a veteran and I’m a professional and I know what I’m doing.’ ”