Storage devices allow for the efficient storage of notebooks on a bookshelf. The storage device includes multiple slots set to predetermined widths and a lip for securing the storage device to the edge of a shelf. Each slot of the storage device is formed by a pair of vertical tabs configured to retain the front cover and the back cover of a notebook. A storage device also includes a first retaining member and a second retaining member which can be slidably positioned to accommodate and retain a notebook having a particular width.
