Task 37 is an international working group which covers the anaerobic digestion (AD) of biomass feedstocks including agricultural residues (e.g. manure and crop residues), energy crops, organic-rich waste waters, the organic fraction of municipal of solid waste (OFMSW) and industrial organic wastes. Anaerobic digestion is carried out in facilities specially adapted for each particular feedstock, or mixture of feedstocks in the case of co-digestion. The main interests are the production of biogas for use directly for heat and power, upgrading of biogas to biomethane, utilisation of biogas/biomethane for electricity grid balancing and high quality digestate that can be used as biofertiliser. Task 37 addresses the whole biogas production chain from feedstock collection and pretreatment to biogas upgrading, biofertiliser application and process chain sustainability.