da Vinci’s commonplace book

"For the most part, his notebooks — like the commonplace books that were kept by students in the Renaissance (Shakespeare's Hamlet had one, for example) — were a polymath's workshop: a place to try out ideas, to develop them over time, and to retain them until circumstances made them more immediately useful.”

“How to Procrastinate Like Leonardo da Vinci” W.A. PANNAPACKER The Chronicle of Higher Education Section: The Chronicle Review Volume 55, Issue 24, Page B4 Feb. 20, 2009 http://chronicle.com