As previously mentioned in this chapter, one of the original drawbacks with the prior implementation of the Client-Side Object Model was its lack of coverage for SharePoint APIs and access to functionality. In the past the CSOM was limited to mostly site, Web, and list operations as part of SharePoint Foundation.
SharePoint 2013’s implementation of the CSOM significantly builds on the coverage of functionality available. It has now expanded to cover most of the surface area of SharePoint Server, not just SharePoint Foundation.
The CSOM is split into a number of different DLLs and namespaces based on functional areas they cater to, which are outlined for you in the following lists. Because the API coverage is so vast in 2013, these lists are only a summary of the most important and widely used areas. They are not exhaustive so you should check MSDN for full reference documentation. Discussing every area of the CSOM would be a whole book on its own so this section is designed to point you in the right area of the CSOM to look for the functionality you desire, as opposed to showing you examples of every area included.
Core functionality contains all the base-level CSOM functionality that you need for working with sites and data. These classes are included in Microsoft.SharePoint.Client.dll:
Content contains APIs for working ...