Lower shows wood broken open. Mixing and Contaminating Bag Contents Paper Records, Photographic Prints, and Packing Materials with high acid content is an on-going and very serious preservation problem. The paper has an extremely high acid content which causes the paper to deteriorate over the course of a very few years. It appears that sweat and body oils accellerate the deterioration. This book is from a project conducted in 1979.
Most pages are beyond salvage.
I've recently discovered others from 1982 in nearly the same condition. Click on pictures for larger view. Damage is caused by pressure of salts crystalizing within objects as they slowly dry, or as temperature and relative humidity fluctuate in their storage area. In fairly porous materials, the salts move to the surface, often causing the surface to slough off in a powder. In denser materials, the salt crystals can't migrate to the surface, and pressures eventually build to bursting.