Hi. I'm a rare book expert. First, keep it stored in a dry place, not too hot or cold, preferably in archival-quality plastic you can get from somewhere like Gaylord.com.

Be very careful when opening it. Don't open it widely when opening it--don't keep the two parts at an acute angle, with the bottom part of the book resting on a table.

I'm wondering about the quality of the paper. Is it fragile, poor quality paper that is starting to fall into pieces? In that case, if it were mine I 'd like to get all pages scanned because the text is very important and you would want to save that as the priority. But handling it like that will cause further damage to the binding. It's a trade off. You might want to get the book rebacked--basically give it a new spine, after scanning it. The pages will hold together and the front and rear covers will be preserved, but the original spine will likely be thrown away. But the book can then be handled more easily and will last longer as an heirloom.

If you want to preserve it as a book, and don't want the spine replaced, then get an archival book box you can snugly store it in. Handle with caution. Store flat.