There appears to be a disagreement between Pearce and the IA State on the use of freezing. IA State says that freezing buys time for dealing with wet books in a manageable way, first by allowing you to put wet books on hold while you work on other water damage, and then by letting you triage the books for careful drying. Pearce seems to imply that the books will dry while frozen, I think.

IA State does say that there are commercial freeze-drying companies that can dry frozen items. This would remove water by sublimation, bypassing the liquid state and its associated problems. I would imagine that such a thing would be rather expensive, however. Alternatively, they give instructions for conventionally drying books after they are thawed.

It is possible that if Pearce does mean that frozen books will become dry, he may have experienced a type of freeze-drying that can occur in a frost-free type of freezer. Such freezers cycle their temperature between the frozen minimum to some higher temperature that lets them remove frost by circulating cold air. This would constitute a type of ambient-pressure freeze-drying that would also involve sublimation.

Vacuum freeze-drying is used to preserve biological macromolecules such as DNA or proteins. Vaccines may be treated in this way for storage and shipment, I think, through a process called lyophilization. The preserved material can be reconstituted to nearly-full biological activity, implying good structural preservation down to the molecular level. Similar treatment of books and papers may yield similar levels of success, except that gross structural changes, such as swelling of fibers, will be preserved after drying, since the evacuated water will leave voids in the material.

This process has also been used to preserved deceased pets with remarkably life-like results (shudder).