the problem is also that in "modern" books (like 50s, 60s, 70's and so on) these books themselves also tend to decay and just crumble after a time, due to some sort of process they do to the paper to create it. In order to truly preserve them you'd almost need like some sort of conditioned environment with the same temperature, no sunlight, stuff like that. Its a shame really, then again nothing in the world was meant to last forever.