Microsoft has released documentation on their Office binary formats. Before jumping up and down gleefully, those working on related open source efforts, such as OpenOffice, might want to take a very close look at Microsoft's Open Specification Promise to see if it seems to cover those working on GPL software; some believe it doesn't. stm2 points us to some good advice from Joel Spolsky to programmers tempted to dig into the spec and create an Excel competitor over a weekend that reads and writes these formats: find an easier way. Joel provides some workarounds that render it possible to make use of these binary files. "[A] normal programmer would conclude that Office's binary file formats: are deliberately obfuscated; are the product of a demented Borg mind; were created by insanely bad programmers; and are impossible to read or create correctly. You'd be wrong on all four counts."