Abstract: In a process for drying paper, in particular whole books but also other absorbent and in particular organic materials present in particular in layered or laminated form, to achieve residual moisture contents of 1% and below in the shortest possible time and without other disadvantageous effects on the paper or the books, in particular as a first treatment step in the mass deacidification of paper, the paper is heated by being acted upon with warm air and dried by being acted upon with reduced pressure. The operation of acting upon the paper with reduced pressure is effected periodically.