Below is an example of a large "Family Bible" that we often see in our shop for restoration or repair. Typically the spine has fallen off completely or is only attached to one cover. Sometimes we can save and reattach the spine.
In other cases we make a new spine that matches the original as closely as possible. We can use either cloth, imitation leather (usually a cloth base with acrylic coating) or genuine leather, that we have in stock. The cost of repairs like this one are vary from book to book depending on the total work involved in each case.
BELOW: These photos were taken after the original cover was dyed and some leather dressing was applied to reinvigorate the original leather somewhat. After dying it's very difficult to notice where the new spine stops and the original cover begins.
RIGHT: This Bible is one that came to us well used. We rebound the entire text block, added a new ribbon, made a new flex cover, removed tape and repaired pages where necessary for page attachment. We didn't repair every little tare although we did smooth out the dog-eared corners.
LEFT: Here is the completed book. The spine is no longer concave and the tape was successfully removed. In this case the customer asked for spine stamping only on the new cover. The imitation leather was wrapped around thin boards to make a flexible cover similar to the original.