Can I use Wikipedia articles (under creative commons) to write a book and sell it? I read the rules for using Wikipedia articles but I am still not sure I properly understand it. I want to write a book using those articles and then sell the book. Can I do it?
On the question of whether the Wikimedia Foundation would object, the summary box at the top of the page here says you are free to share and adapt what you find on Wikipedia, as long as it is attributed (the source is cited) and you understand that anyone buying (or even reading) your book would be free to share and adapt your book for any purposes, including commercially (ie. the Creative Commons License continues through your book to subsequent users of the information).
If the question of whether you could sell the book is more one of "is anyone going to buy it?", it would be worth identifying your target market and considering what your book would offer them that they couldn't find by viewing Wikipedia - the "added value" that your book would be providing.
With Wikipedia being what it is, there may also be amendments to the pages you have used in your book, and by the time the book is published there could be more recent information available.
It's a slightly different question, but this previous answer had some good information and further links on Creative Commons licencing.