MAGNET (Modular Applied GeNeral Equilibrium Tool) is a global general equilibrium model. A distinguishing feature of the model is its modular design. Modularity allows modellers to tailor the model structure to fit the research question at hand. MAGNET is based on the LEITAP model, which has been used extensively in policy analyses. MAGNET offers more flexibility in model aggregation (definition of regions and sectors) and more options for changing a model’s structure. The main purpose of MAGNET is to provide a globally applied general equilibrium modelling framework.With the standard GTAP model as the core around which MAGNET was developed, use of MAGNET requires, at a minimum, an understanding of the standard GTAP model and the ability to read GEMPACK code. Therefore, in the following MAGNET documentation, neither general equilibrium modelling nor the GTAP model is discussed. We do describe, for each of the extensions MAGNET makes to the standard GTAP model, the aim of the extension, the theory underlying the module, the additional data requirements needed to run the module and instructions on how to activate the module.In this chapter, we describe the main coding conventions used in MAGNET in order to facilitate reading of the code. Documentation on how to run MAGNET from scratch is available in the last chapter. More information on how to adjust the MAGNET model for developers is available in several of the early chapters of this manual.