This chapter provides the first part of an evidence base of practices in industrial symbiosis. We reviewed twenty-five case studies to build a rich picture of the various triggers that seed or accelerate resource synergies between organisations. We identified triggers that operate at various levels in relation to industrial symbiosis. These are categorised as national governmental, regional and firm levels. We found that there is a high degree of interplay between these levels. Catalysing industrial symbiosis is complex and context specific. The lessons learnt illuminate the path dependent nature for the scale up of industrial symbiosis.