http://192.168.2.20/blogs/doverton/archive/2007/11/27/office-open-xml-file-format-information-or-standard-ecma-376-and-the-ooxml-sdk-information-on-msdn.aspxI saw this question asked internally today, so I thought I would share. If you want to develop to use the Open XML document format you probably want to look at two things. The Microsoft resources (eg http://msdn2.microsoft.com/en-gb/office/aa905545.aspxenCommunityServer 2008.5 SP2 (Build: 40407.4157)