If I had a suitable image I would offer it. I don't see a problem in having your work in a book with no monetary return. I don't do photography for a living and don't expect to make any money from it.

Equally I don't make my living working as a plumber or carpenter but often do such work on friends houses. I don't see this as de-valuing the plumbing or carpentry professions either.

I would be very happy to see one of my images in a book with nothing more than a credit and perhaps a copy of the book in return.