We have some Boy Scouts whose books are falling apart. For the worst case I put all the loose pages in, lined it up perfectly, then loaded a small (numbered drill bit - smaller than the 1/16th in a normal bit set) and drilled holes through the pages on the binding edge of the book, about 3/32 inch in from the edge and about 3/16 inch apart.
Then used some very tough button thread and sewed the book together top to bottom and back, finally tying the ends (and melting the thread ends as it was nylon.)
Since the gutter margin (inside edge margin) is deep enough in a Boy Scout Handbook this solution can work, and the book can be read and used. - The Scout was impressed and happy enough that his original book and original signed off advancements were saved.
I recommend that the boys use zippered book covers such as are available at Barnes & Noble, and Office Depot... any maybe some other stores. Ziplocks trap moisture and sooner or later may cause mildew.