http://blogs.msdn.com/jmstall/archive/2006/07/03/outputdebugstring-vs-debuggerLog.aspxBoth Debugger.Log and OutputDebugString have some key similarities: The both log string for debugging purposes Both have thread-affinity. (The debugger can find out which thread logged) Data is piped through with no additional semantics in the debuggeren-USCommunityServer 2.1 SP1 (Build: 61025.2)http://blogs.msdn.com/jmstall/archive/2006/07/03/outputdebugstring-vs-debuggerLog.aspx#655415Mon, 03 Jul 2006 21:19:39 GMT91d46819-8472-40ad-a661-2c78acb4018c:655415Mike Stall's .NET Debugging BlogFxCop has a great rule (UseManagedEquivalentsOfWin32Api) to tell you about managed APIs that exist instead...http://blogs.msdn.com/jmstall/archive/2006/07/03/outputdebugstring-vs-debuggerLog.aspx#655496Mon, 03 Jul 2006 23:12:43 GMT91d46819-8472-40ad-a661-2c78acb4018c:655496bgwhat's the diff between Debugger.Log and Debug.Writeline apart from the level category paramshttp://blogs.msdn.com/jmstall/archive/2006/07/03/outputdebugstring-vs-debuggerLog.aspx#655514Mon, 03 Jul 2006 23:35:42 GMT91d46819-8472-40ad-a661-2c78acb4018c:655514jmstallbg - Debugger.Log is the low level managed logging facility in the BCL.  Debug.WriteLine (and Trace.WriteLine) is a higher-lever logging facility that builds on Debugger.Log