This is the original cover painting for the 1979 Corgi (UK) paperback edition of the popular mystery thriller by the well-known American author Irving Wallace, first published 1972.   Featuring a montage of characters from the novel (which concerns the discovery and origin of a fictional New Testament of the Bible), this is stylishly rendered in gouache and acrylic on illustration board c. 12.5" x 11" (the small bits of tape can easily be removed, the piece was photographed to show all details) -  and comes with a label attesting to its authenticity signed by Pether's widow, mounted to the back.