The physical vehicle, such as DNA, can be snipped and rearranged to encode for new information. Computer disks can be erased and reprogrammed. Physically, books are nothing more than paper and ink, and as such, their physical elements follow the laws of physics. The information that the books contain, however, is not subject to the laws of physics. Information can be true, false, fantasy, or nonsense.
Memory is the localized storage of information.
All memory vehicles are composed of the solid state of matter. Liquids and gasses don't work because their molecules are always moving randomly, and they are incapable of holding patterns. A message in alphabet soup is lost when stirred. The ingredients may still be there, but their organized structure, their relationship is not. Light and radio waves can be used to transmit encoded information, but they are not useful for localized memory storage because they travel.