A sliding bookcase is a wooden shelf or cabinet for bound volumes that is designed to move on rollers, a track, hinges, or another mechanism and is typically used to hide the presence of a secret room or space. Sliding bookcases were used in the United States during prohibition to hide rooms or spaces containing liquor. They have also been used to conceal entrances to speakeasy bars and marijuana-growing operations. People have hidden in secret rooms concealed by sliding bookcases to escape detection during police raids or from totalitarian governments.