Please do not do this. One of the fundamental keys to conserving books is to maintain even heat/moisture. Baking books in a home oven is not only a massive fire risk due to the nature of the heating element, but you will shorten the lifespan by a lot. Old book pages already get crumbly when they lose moisture over time. Do not hasten the process by further removing moisture and exposing it heat. You will also damage the binding, melt adhesive, etc. this way.