There are several questions about sample code presented in the newest edition of the Red Book on this forum. The easiest way to help those guys is to build full-working examples. My question is: Do I need some formal approval from the author(s)?

Earlier versions have many authors, but in this one, only Dave Shreiner listed as an author, and I didn't succeed to find his e-mail or any usable contact-information.

And the second question is: May I modify those examples?

Although it sounds like trivial questions, they are not, and I don't want to use intellectual property of other people on illegal way. So, please, give me some useful advices.