I can't imagine what it would have been like to write a CLR/.NET Framework 1.0 book before it was released from the outside. That is, while not working for Microsoft.

I just upgraded from Whidbey Beta1 to PD7, and found a ton of interesting changes. Mostly API renames which, thankfully, are done through obsoleting the old one. This makes migrating much smoother since the build doesn't break, and I can just follow up on the warnings as needed. I have to be better about keeping up from drop to drop. Even without doing that, though, every so often I get wind of a change via email or word of mouth, and make a note to check it out at some point in the future. I basically have a whole set of Outlook folders, one for each chapter, with nearly one hundred todo's... One has to wonder if I'll ever be able to follow up on them all. :)

Luckily, I also have a whole suite of test cases which I am using to verify when something changes. Basically, anything I write about, I write a test case for. This has definitely been one of the best decisions I made towards the beginning of the project. This at least helps to identify areas where the text might now be out of date, and points directly to code samples which are obsolete.