Selected pages from the Spätgotisches Musterbuch des Stephan Schriber
, a manuscript which appears to be some kind of sketchbook, belonging to a 15th century monk working in South-West Germany, where ideas and layouts for illuminated manuscripts were tried out and skills developed.
(All images taken from the Bayerische Staatsbibliothek
found via Europeana
Monks were the desktop publishers/artists of their time. This is a stunning look into the development of the skills used to produce handcrafted works of art in the form of books. Amazing!