In a recent interview with Reuters, Facebook Chief Operating Officer (COO) Sheryl Sandberg said that there is no plan by Facebook to lift its ban on President Trump on the platform. Sandberg said, “the risk to our democracy was too big that we felt we had to take the unprecedented step of what is an indefinite ban and I’m glad we did.”

Social Media companies have undertaken an unprecedented purge of conservatives and ideological dissidents from their platforms. Here are 6 must-read books to understand what is going on.