The Lost Art of Phrenology

Wilhelm von Gwinner wrote three biographies of his friend Arthur Schopenhauer: in 1862, 1878, and 1910. His granddaughter Charlotte von Gwinner edited and annotated them, producing a couple more versions in 1922 and 1963.

I just received a copy of the one published at Leipzig by F. A. Brockhaus in 1910, and discover that it contains this glorious foldout:

Translation: A geometrically accurate outline of 
Schopenhauer's skull, based on a plaster cast