How do I repair an old leather-bound book?

I’ve got a old leather-bound book. Dropped it accidentally the other day and the spine broke away on one side; still connected on the other side.

What’s the best way to repair it? Normal white glue probably isn’t very good because it set hard

Woe something like Lepage’s rubber cement be better? Would it keep it flexible enough?

Apparently the best glue for repairing leather books is PVA aka normal white glue.

If its something important to you or valuable to the market, seek a professional. It will take time and cost like the dickens but anything you do at home will be as much damage as repair.

That being said, I have a couple basically worthless old (1740s) books I keep to read around camp at historic events. For them I use white glue for spine repairs and then sometimes reinforce the repair by white gluing a strip of pillow ticking over the whole spine and partly into the front and rear boards.