You would need to read the GPL to be sure, but I believe it is, as long as you make clear that that portion of the book is free for usage under the GPL (or the appropriate license for the man page in question).
In my early days with Linux I purchased a book (I forget the name and I've long since donated it to some thrift store) that turned out to be a compilation of man pages. I did not regret the purchase. Sometimes nothing beats a book.
You may find the answer to your question here: http://www.gnu.org/licenses/gpl-3.0.en.html
I recommend the FAQ page.