At the invitation of a discreet literary magazine, the Feu Follet bookstore was recently invited to share its view on a venial sin of the bibliophile, the handwritten annotation on books known as marginalia. This offense for some, an offering for others, has a history as old as the book and has inspired this new investigation. How can we trace the history and importance of these annotations which flourished from the outset on the margins of printed matter?