Leonardo's Cartoon of the Virgin and Child with S. Anne and S. John the Baptist, part of the collection of the National Gallery, is probably dated 1507-1508. Recent restoration work allowed the study of the techniques of the cartoon and its vicissitudes. This contribution is articulated in three parts: the history of the cartoon by Martin Wyld which discusses the original materials and the possible methods of repair, in particular the damage caused by a shotgun in 1987; the repair and restoration by Eric Harding which describes in detail all the process (flattening of the Cartoon, removal of fragments from the area of damage, removal of the old stretcher, new support, return of the fragments, restoration); materials and techniques by Aviva Burnstock which studies the paper, the surface-coating and the drawing materials.