The books depict patterns of sheep marking, in the ear and on the wool, and name their owner with her/his residence.
One of the earliest Shepherd's Guide was prepared for parts of Cumberland by Joseph Walker, in 1817.
While all of those feature a detailed engraving of sheep (repeated with different marks), the books from the late 19th and 20th centuries have a line sketch.
The later books are attributed to various farmer associations, and cover a wider perimeter.
The books are useful as a genealogical and local history resource, and as collectibles.