We have announced today the release of version 1.0 of technical documentation for a variety of protocols used by Office, SharePoint and Exchange. this brings the total amount of protocol documentation available for free download on MSDN to about 50,000 pages, including 5,000 pages of new documentation for the binary file formats alone.
The binary format documentation is thorough and well-organized, and will be useful to anyone who needs to write code that reads existing binary documents. Here, for example, is a diagram showing the basic structure of tables in the .DOC format:
And here's a diagram that shows how metadata is organized in a spreadsheet file:
Speaking of spreadsheets, this new batch of documentation also covers the XLSB format that is used in Office 2007 to optimize performance in unusually large and complex spreadsheets. For a full list of what formats are covered, see the MSDN site.
The documentation is supported on a group of User Forums that are organized by general topic. If you have specific questions about the details, that's the place to get them answered, and for more information about the things we're doing to enable interoperability with Office see today's press release or the Microsoft interop site.