Expandable book cover

An expandable cover and a book of materials, such as data processing sheets, accounting records, and the like, comprising:

• a pair of leaf boards overlying the front and back sides of said book forming the front and back covers of said book,
• case made folded cloth members adhesively joined to both the inside and outside of the inner ends of said cover boards and extending beyond them in spaced relationship,
• a pair of corner members adhesively secured on their inside and outside to said cloth members and spaced slightly from the inner ends of each of said cover boards to thereby hingedly join said cover boards to said corner members, said cloth members extending on both sides of said corner members and beyond them around the corners of said book in spaced relationship,
• means secured to each of said corner members and extending through said book for adjusting the spacing between the corner members,
• a pair of spine protecting and covering elements each comprising a pair of members separated at their edges adjacent the front and back of said book by narrow spacer strips joined to said pair of members to define an extensive opening between each of said members, said cloth members being adhesively connected to the outsides of each of said pair of members to join said pair of spine protecting and covering elements to said pair of corner members;
• and
• an element slidably positioned and received in said openings to completely cover and protect the spine of said book and permitting adjustment of the spacing between said front and back covers.