The electromagnetic and thermal analyses of a mode-stirred chamber designed for the heat treatment of antique and precious books are proposed. In particular, the electromagnetic and thermal perturbations due to the presence of metallic insets inside the treated material (paper) are investigated. The temperature measurement results obtained by thermography and by temperature fiber-optic sensor are also reported. Finally, metallic shields are experimentally demonstrated to prevent the overheating of the treated material and the consequent damage of the antique tomes.