> If I take a chapter of a textbook, modify it to be a standalone volume in a collection of books and start distributing it, I am distributing a derived work of

> If I take a chapter of a textbook, modify it to be a standalone volume in a collection of books and start distributing it, I am distributing a derived work of the original book, not a derived work of the collection of books. The latter constitutes an aggregation and unless there is some license (superseding doctrine of first sale in the case of books) that prevents it from being redistributed with such things, it is perfectly okay to do that. I should elaborate that you need the original to be under license. Otherwise, you have a problem.