In the Peruvian Amazon, the production of reliable state information about rainforests has been one of the most enduring and difficult problems faced by generations of state bureaucrats and engineers. While anthropologists in Amazonia and elsewhere have consistently examined the differences between technical forms of knowledge and the affective and embodied experiences of rainforest dwellers, the complex processes through which technical and bureaucratic information about rainforests is produced have been relatively underexplored. My research will examine the practices of material inscription, circulation and contestation through which state information about tropical rainforests comes to be composed and managed in the Amazonian region of Loreto, Peru. It will do so by analyzing the ways in which field engineers perform various kinds of technical inscriptions in the rainforest that subsequently come to circulate into the offices, desks and computers of bureaucrats, where legal, ecological and economic facts about rainforests are then constituted, contested and stabilized. I will analyze these processes within two economies of rainforest information around which several contemporary anxieties are being woven: the traceability of timber and the determination of its legality, and the legal fixation of indigenous land rights and the determination of their boundaries. By analyzing these economies of rainforest information, I will shed light upon how nonhuman forces such as the distribution of trees or seasonal floods decisively shape how state rainforest information is produced. Similarly, I will analyze the various forms of contestation, controversy and undecidability that inform the production of these seemingly neutral and impersonal bodies of rainforest information.