John Cotton Dana,
Notes on Bookbinding for Libraries
“ Books which have one or both of their sides broken, but are otherwise perfect, can have their boards replaced. Do not do this to books in publisher’s binding, as such books will soon have to be rebound in any case.On a book which is hand sewn, with leather back, a broken board can be replaced thus: Pull off the cloth side, lift up the leather carefully where it laps over the side, also the muslin on the inside and pull out the broken board. Put hot glue along both edges of new board to be inserted, and put in place. Rub down well, and put under pressure, then reside and insert new end leaf. ”
