When the height is greater than or equal to 1500mm, the fixing frame shall be fixed. According to the "General Technical Conditions for Bookshelves", the man-machine requirements for bookshelves are: when the height of fixed bookshelves is greater than or equal to 1500mm, they should be fixed. A book is a medium for recording information in the form of words or images, and usually consists of many pages (made of papyrus, parchment, kraft paper or paper) bound together and protected by a cover.