The Internet was designed without a clear plan for handling identity, which resulted in a patchwork of custom solutions springing up—all of them not long term solutions. With exponential increases in malicious activities that pervert these systems, the Internet clearly needs a single-sign on solution that can span platforms and technologies. The concept of an identity metasystem was proposed (a whitepaper on the identity metasystem can also be found on www.identityblog.com). The identity metasystem describes a platform agnostic way of communicating and validating claims of identity, and is heralded not just on the Microsoft web site, but in places like the cover of Linux Journal. Microsoft built their implementation, Windows CardSpace, on top of the identity metasystem, and is working with key players you’d expect – and some you might not – to make sure this is success and interoperable. The book provides a baseline in identity, including coverage of identity concepts, the laws of identity, and the identity metasystem. From there, the focus is on Windows CardSpace – what it is, where you could use it, where you should use it, and how you would implement it. Coverage of how to implement the technology for use on the web and via services is included, as are multiple case studies that showcase different scenarios where the technology is employed.