Excel Primary Interop Assembly Reference
The Microsoft Excel 2013 Primary Interop Assembly (PIA) Reference provides help for developing managed applications for Excel. It extends the Excel 2013 Developer Reference from the COM environment to the managed environment and focuses on how to use the PIA.
If you use Microsoft Visual Studio 2008 Tools for the 2007 Microsoft Office System or Office Developer Tools for Visual Studio 2013 and you are connected to the Internet, you can access context-sensitive Help when you press F1 in the Visual Studio integrated development environment (IDE). This Help content is the Excel 2013 PIA Reference on MSDN.