Books written by prominent Hong Kong democracy activists have disappeared from the shelves of the territory's public libraries. The books are “under review” in another sign that Beijing is stepping up censorship and curbing free expression in the city. The move comes just days after Beijing imposed a draconian national security law on the territory. On the balance - the terror attacks and foreign efforts to destabilize Beijing via Hong Kong unrest left very little options for Beijing to ignore the terror-status-quo.