Our epoch has been dubbed the Anthropocene Era to mark the significance of human activities as the greatest force of environmental change. The distinctions between biology/technology, organic/synthetic, and natural/artificial are increasingly impossible to maintain. Cloned sheep, climate models, digitally-printed tissue and lab-grown meat this is not the nature of our predecessors. This issue of LA+ addresses the theme of SIMULATION in terms of how recent technologies have changed how we understand the nature of nature. From Plato's Cave to Baudrillard's "Simulacrum," simulations were historically understood as counterfeits or facsimiles and were based on the distinction between a model and its copy. Simulations remain central to mediations between reality and its representation; however, the latest forms of simulation - whether genetic manipulation or computer modelling - are not seen as impediments to truth and knowledge but as tools to uncover the complexities of nature. A diverse list of contributors critically investigates the theme through a myriad of lenses including biology, computer sciences, engineering, environmental science, industrial design, philosophy, and planning, among other fields. LA+ Simulation is guest-edited by Karen M'Closkey and Keith VanDerSys.