This work is licensed under a Creative Common Attribution-NonCommercial-ShareAlike 3.0 Unported License. This license is available at creativecommons.org/licenses/by-nc-sa/3.0/.
I would have preferred to license the book under the less restrictive CC-BY-SA license. But unfortunately there are a few unscrupulous organizations who search for and find freely licensed books, and then publish and sell virtually unchanged copies of the books on a print on demand service such as LuLu or CreateSpace. CreateSpace has (thankfully) added a policy that gives the wishes of the actual copyright holder preference over a non-copyright holder attempting to publish a freely licensed work. Unfortunately there are many print-on-demand services and very few have as well-considered a policy as CreateSpace.
Regretfully, I added the NC element to the license this book to give me recourse in case someone tries to clone this book and sell it commercially. Unfortunately, adding NC limits uses of this material that I would like to permit. So I have added this section of the document to describe specific situations where I am giving my permission in advance to use the material in this book in situations that some might consider commercial.
If you are intending to translate the book, you may want to contact me so we can make sure that you have all of the related course materials so you can translate them as well.
Of course, you are welcome to contact me and ask for permission if these clauses are not sufficient. In all cases, permission to reuse and remix this material will be granted as long as there is clear added value or benefit to students or teachers that will accrue as a result of the new work.
Ann Arbor, MI, USA
September 9, 2013