What do the children do with books ? A key concept in childhood studies since the 1970s, children's agency has recently returned to the heart of the reflections of a group of childhood historians. The conference Se soustraire à l'empire des grands. Enfance, jeunesse et agentivité (1500-1830) (escaping the empire of the grown-ups: childhood, children and agency (1500-1830)), organised by Sylvie Moret-Petrini at the Université de Lausanne, focused on the personal journals of children and adolescents. The aim was to tackle this source, often seen by historians as a surveillance and educational tool, or as 'panoptiques de papier' (paper panopticons), from a new angle and consider it as a space where young writers could reflect on their status as children and express forms of rebellion or indiscipline. These reflections invite us to take a fresh look at another object that educators advised should be placed under the constant and close supervision of parents, namely the book. What kind of agency can be achieved in children's and adolescents' relationships with books, whether this was how they approached and absorbed texts, how they handled the book as a physical object, or the resources they drew from their reading to inform their present actions or future choices? This approach, as always, requires a cross-analysis of the rare traces left behind by childish handlings and the mass of adult, pedagogical, parental, medical and literary discourse. It is clear there was plenty of room for manoeuvre concerning ways of reading, places and times of reading, and the material uses of the book as a physical object. Those who enjoyed reading as a child recall their ability to fully immerse themselves into the imaginary world opened up by a text, like children who play at being a fairy or Robinson Crusoe. In adolescence, parents express the fear that certain books may cause their offspring to 'emulate something unusual' or to take up careers other than those they had envisioned for them. The 'wild' handling of books is documented by the volumes themselves, such as the practice of writing and drawing in the margins, either to pass the time or to convey messages to someone sitting nearby [fig. 1]. We find examples in literature and art of children making castles out of books or using them as stepping stones, like the Cholmondeley children painted by Hogarth in 1732 [fig.2]. However, beware of such overly euphoric representations of childish creativity. Alongside these noisy diversions, there were also quieter forms of agency, 'weak uses' of books such as interrupted or unengaged reading, or expressions of a dislike of reading (sometimes found in correspondence or in parents' diaries), which were all ways of rejecting the pedagogical norms of consulting books as a means of self-improvement and learning. As is often the case, most traces of or clues to the agency of young readers are available to the historian only through writings originating from the adult world (theoretical discourse,