Here are some of my favourite books for writers which I recommend to students. I've been inspired by them for myself, and adapted from them for class exercises -- and gained permissions and given thanks for this in my book of exercises for tutors. So if you want to grow your shelf, and yourself, have you seen:
Writing Down the Bones by Natalie Goldberg, Shambhala, Boston, 1986.
Writing on Both Sides of the Brain by Henriette Anne Klauser, HarperCollins, New York 1986.
Writing for Your Life by Deena Metzger, HarperSanFrancisco, New York, 1992.
Fiction Writer's Workshop by Josip Novakovich, F+W Publications, Cincinnati, 1998.
The Weekend Novelist by Robert J Ray and Bret Norris, A&C Black, London 2005.
There are lots of other sources, including books, authors, poets and more in the bibliography at the back of Creative Writing: the Matrix.
I would like to add a links page to this blogspot, full of useful sites to creative teachers. If YOU have favourite creativity & creativity-teaching books or websites to share, do let me know by post-comment.