6 important .NET concepts: Stack, heap, Value types, reference types, boxing and Unboxing.

1. For english version:

http://www.codeproject.com/KB/dotnet/6importentStepsDotNet.aspx

http://www.csharpcorner.com/uploadfile/rmcochran/csharp_memory01122006130034pm/csharp_memory.aspx

2. 中文翻译版： 详解.NET中六个你必须知道的重要概念(1)

http://developer.51cto.com/art/201005/197729.htm

http://www.cnblogs.com/niyw/archive/2010/09/20/1832077.html