Anyone taking a first look at SAML will see that is complex. As well as being a good tool to implement Single Sign-On ease organizational pain and improve security, it can also be a source to critical security vulnerabilities if design or implemented incorrectly.
SAML 2.0: Designing secure identity federation demystifies the concepts of SAML and gives beginners, as well as experience architects, a good understanding of the otherwise complex subject of SAML.
Walking through all topics from introduction to advanced you will learnTo fully understand SAML and identity federationWorkings of the main building blocks like NameId, bindings and assertionsHow Single Single-On and Single Logout works in detailDifferent architectural choices and implementation alternativesSecurity best practices and considerationsPrevious security vulnerabilities and what can be learned from them