We introduce a number of techniques for establishing the deadlock freedom of concurrent systems. Our methods are based on the local analysis (or at worst a directed global analysis) of networks. We identify the relationships between these techniques and the range of their application within a framework of deadlock freedom types that we have defined. We also show that the problem of proving total correctness may be translated to one of proving deadlock freedom, with the consequence that our techniques for proving deadlock freedom may be utilised to effect a total correctness proof.