A general set of topics about Shibboleth can be found in the Shibboleth Concepts wiki space. The following are supplemental topics specific to the Shibboleth V2 IdP and SP software products.

A page describing key differences with the older V1 software is here.

Authentication and Sessions
Service Provider / Relying Party types

Software Architecture
How Attributes are Retrieved
Services, Applications, and Resources
Can a single installed SP protect many servers?