Under the generic title, ‘French Crossings’, this Presidential Address explores the history of laughter in French society, and humour's potential for trangressing boundaries. It focuses on the irreverent and almost entirely unknown book of comic drawings entitled Livre de caricatures tant Bonnes que mauvaises (Book of Caricatures, both Good and Bad), that was composed between the 1740s and the mid-1770s by the luxury Parisian embroiderer and designer, Charles-Germain de Saint-Aubin, and his friends and family. The bawdy laughter that the book seems intended to provoke gave it its nickname of the Livre de culs (Book of Arses). Yet despite the scatological character of many of the drawings, the humour often conjoined lower body functions with rather cerebral and erudite wit. The laughter provoked unsparingly targeted and exposed to ridicule the social elite, cultural celebrities and political leaders of Ancien Régime France. This made it a dangerous object, which was kept strictly secret. Was this humour somehow pre- or proto-Revolutionary? In fact, the work is so embedded in the culture of the Ancien Régime that 1789 was one boundary that the work signally fails to cross.