1. Introduction & Purpose The Gyproc Doe Book (often derived from the Dutch word "Doeboek" meaning "Activity/Work Book" or simply the standard trade name for the Gyproc handbook) is the essential technical manual published by Saint-Gobain Gyproc . It serves as the authoritative guide for the correct handling, installation, finishing, and specification of gypsum plasterboards and associated systems (partitions, linings, ceilings, and shaft walls).