We covered a lot of ground to become familiar with the foundations of PAPI. In this chapter we established that nearly every CMS project will need to use PAPI. We discussed the need for a new .NET-based PAPI, and we touched on the legacy COM-based API. We introduced the concept of Context and its importance to the CMS infrastructure. We discussed the details about significant objects found in the PAPI object model, the principal objects among them, and their relationship to one another. We talked about the base classes (common functionality) and namespaces (class organization) used by PAPI. In the next chapter, we delve deep into CMS Context, the key to accessing all other CMS objects.