Existing methods of deacidifying paper have limitations caused by dependence on the use of liquids. A promising new method, vapour phase deacidification or VFD, is proposed, involving the use of a volatile alkaline amine, cyclohexylamine carbonate. Bound books may be deacidified by interleaving them with paper impregnated with CHC, or packets of the compound may be placed in boxes of loose documents. The degree of deacidification can be checked with the indicator dye bromcresol green applied with a felt-tipped pen or rubber stamp. Limited aging tests indicate that the treatment is permanent. CHC is believed to be not seriously toxic, and its odor gives sufficient warning to prevent irritation. Efforts are being made to offer the product commercially. -- AATA