To understand the Windows Security

There are many references existing in MSDN to talk about Windows Security. Some of them are for the new users, but some of them are for experienced users or even programmers. Moreover, they explain the concepts in different ways for different version of Windows or .NET Framework. It's still frustrating to search through all those documents and check them one by one.

During search the fundamental comprehensive documents, I found this link is quite useful:
[MS-SECO]: Windows Security Overview
Not only you can learn the overall fundamental knowledge of Windows security online, but you can aslo download the whole topics in PDF format from the link side to read offline.

Actually, when you go upper level of the we site, you will find that link provides many documents for all Windows protocols:
Windows Protocols

And Microsoft keeps updating those documents!