Books and doors are the same thing.
You open them, and you go through into another world.
~ Jeanette Winterson
The books on the following short list have provided solid support for my writing practice:

The Artist’s Way: A spiritual path to Higher Creativity – Julia Cameron

Writing Down the Bones: Freeing the Writer Within – Natalie Goldberg

Fingerpainting on the Moon: Writing and Creativity as a Path to Freedom – Peter Levitt

Saved by a Poem: The Transformative Power of Words – Kim Rosen

Writing Alone and with Others : Pat Schneider