A book doesn't get finished all of a sudden. It happens in stages, and by the time you realize that there's nothing left to do because your publisher has sent the files to the printer, the work has pretty much dwindled down and it's hard to figure out when you should have celebrated.
However, one very significant milestone in completing a book — emailing the final chapter of the manuscript to the Project Editor — happened yesterday for Programming Microsoft Windows Forms. That was a comfortable two days ahead of schedule, and reason for great jubilation.
(I must confess that one incentive for finishing that chapter yesterday was to enable a guilt-free drive into the city today for the final regular-season at-home game of our beloved New York Liberty. It's Fan Appreciation Day, and that means free tee-shirts.)
What's left with the book? After my editors edit each chapter, the Word documents come back to me for my review. I need to answer questions, fix things, make last minute changes, and ensure that the editing didn't alter my meaning. Of the 7 chapters in the book, I've already reviewed the first three, I have Chapters 4 and 5 sitting here patiently awaiting my attention, and 6 and 7 have yet to be returned (which is reasonable because I only sent them in this week).
The next stage involves PDF's of the chapters. I can still make fixes at that point, but major changes are discouraged, particularly anything that affects page flows. The nice thing about the PDFs is that they finally make the manuscript look like a real book.
Of course, there's always a chance that a later beta of .NET 2.0 will break something. That's always fun.