This book explores the level of understanding of identity management architecture along with its place in the literature and its use in industry. This book is based on research into a case study of eight Australian public sector agencies that had designed identity management systems. This case study identified the major elements of identity management systems and enabled the development of an Identity Management Architecture (IdMA). The IdMA was designed as a series of frameworks that integrates identity management into the existing policies, processes, workflows, technologies and data of an enterprise. Each framework combines one or more identity management elements, along with the relevant enterprise processes and workflows, into an integrated set of enterprise process and workflow. Now both researchers and practitioners have access to a reference architecture that illustrates how the different frameworks relate to each other and to the processes and workflows of the enterprise. The IdMA provides researchers and practitioners with architectural guidance and information for the design of identity management systems.