Marginalia (plurale tantum)'s the general term for notes, scribbles, and editorial comments made in the margin of a book. The term's also used to describe drawings and flourishes in medieval illuminated manuscripts. True marginalia isn't to be confused with reader's signs, marks (for example stars, crosses, fists) or doodles in books. The formal way of adding descriptive notes to a document's called annotation. The scholia on classical manuscripts are the earliest known form of marginalia. Ferm… (More on Marginalia)