It is based on the 21 volume Le Peintre-Graveur, by Adam von Bartsch, published in the early nineteenth century, which listed the prints and gave a concise description without illustrations, noting different states.
The continual evolution of art history and scholarship provide new additions and attributions (as well as de-attributions), which have caused the project to grow exponentially.
After Strauss' death in 1988, Abaris Books was made an imprint of OPAL Publishing Corporation, which continues to produce volumes under his General Plan.
Emphasizing new attributions, de-attributions, additional states, and copies (among others) maintains the usefulness and pertinence of the historical art collection as scholastic reference works.
These volumes consist of German Single Leaf Woodcuts before 1500 by Anonymous Artists, as organized by Wilhelm Ludwig Schreiber and originally published in the early 20th century.