Where is the best documentation of Microsoft Excel Biff format

Question

I am looking for the best documentation of Microsoft Excel's file format - 1997 - > 2003. I am not looking for ooxml. What is the best resource on the web?

Answer 1

Here:

http://www.microsoft.com/interop/docs/OfficeBinaryFormats.mspx

Answer 2

Published by Microsoft. http://www.microsoft.com/interop/docs/OfficeBinaryFormats.mspx