Although rarely in the spotlight, mountaineering equipment is much more than just an accessory for climbers. Its evolution bears witness to climbers’ ingenuity in overcoming ever more challenging obstacles and also embodies ethical choices. In short, these tools reflect their users’ relationship with the vertical world. For forty years, Petzl and its founders have been key players in the great history of mountaineering. As heirs to the golden age of caving – in which Fernand Petzl was a leading figure – the manufacturer has explored various aspects of the vertical world: rock, ice, snow, night-time… It has also applied its expertise to the fields of rescue and work at height. To read about the Petzl adventure is to follow the men and women dedicated to the worlds of verticality and exploration. In constant interaction with an ever-changing environment, they invent the means to push forward.