Under normal circumstances wood is subjected to the attacks of deteriorating agents, like fungi, insects, etc. Modern wood preservers can protect wood from deterioration, however, they can not restore the structural strength of already deteriorated timber. The WER-System makes it possible to restore the original structural properties of deteriorated timber. It can usually be applied in situ, without altering significantly the outside appearance of historically or artistically important wooden surfaces. It involves the rehabilitation of the deteriorated wood with specially formulated epoxy resins and high tensile inserts. The system has been thoroughly tested in a number of government and private laboratories in Canada. This handbook describes step-by-step the application of epoxies, the installation of reinforcing elements and the design calculations for the system. Specifications and sources of the epoxies are listed. The book is written primarily for professional conservators, architects, engineers and contractors who are engaged in the restoration of historic or artistic buildings, structures and larger artifacts. -- AATA -- AATA