Also by Stonehenge
We're writing Learning Perl 6, the Perl 6 version of our Learning Perl. O'Reilly Media has accepted the proposal and we're negotiating the contract.
We're running the entire project "transparently", meaning just about anyone is free to take part, review the intermediate drafts, or make comments. You get to see how a book goes from the idea to the final product, and I get a better book as a result. At the moment I'm developing the outline for the book. You can read the proposal.