I am not sure what to think about this book. It starts out annoyingly simplistic then exponentially picks up the learning curve through the protocols and tokens section and finishes out with a walk through of Microsoft ADFS. If there is anything to take away from this is a good understanding of authentication, authorization and federation.
All IT professionals need to be familiar with these technologies that are finally being leveraged due to the out of control nature of cloud based technologies serving the needs of the organization. Reading this book is helpful but you could probably get more out of reading about OAuth, SAML and OpenID on your own.