This letter was sent individually to each Catholic bishop in the United States. 132 Catholic professors signed the letter. It is the most wonderfully written letter I have seen on this topic. Here is an excerpt regarding the CCSS's new emphasis on "informational texts" including government documents and regulations and away from classical, narrative fiction:
Professor Stotsky was the chief architect of the universally-praised Massachusetts English language arts standards, which contributed greatly to that state's educational success. She describes Common Core as an incubator of "empty skill sets...[that] weaken the basis of literary and cultural knowledge needed for authentic college course work." Rather than explore the creativity of man, the great lessons of life, love, tragedy, good and evil, the rich textures of history that underlie great works of fiction, and the tales of self-sacrifice and mercy in the works of the great writers that have shaped our cultural history over the centuries, Common Core reduces reading to a servile activity.
You may read this brilliant letter and see the signatory list here.