Art and Fear, by David Bayles and Ted Orland ( this is a small no-nonsense book about making art and it is wonderful) My Favorite.
The Courage to Create by Rollo May. Read this a long time ago and found it helpful. Old, paperback.
Creative Authenticity, 16 Principles to Clarify and Deepen your Artistic Vision.
No More secondhand Art, Awakening the Artist Within by Peter London
Free Play, The Power of Improvisation in Life and the Arts. Stephen Nachmanowitch
Blank Canvas, Inviting the Muse, by Anna Held Audette
Art is a Way of Knowing, Pat B. Allen
Trust the Process, The Artist's Guide to Letting Go, Shaun McNiff
The Artist’s way, Julia Cameron
How to avoid making Art, Julia Cameron (Drawings by Elisabeth Cameron)
The Creative Habit, Twyla Tharp
The War of Art: Winning the Inner Creative Battle, by Steven Pressfield
Color by Victoria Finlay, a mix of history, symbolism, theory etc. all presented in a very readable manner.
The Primary Colors by Alexander Theroux and the Secondary Colors by the same author. ( The meaning of each color at length, it is fun to dip into)
Color, The story of Dyes and Pigments Francois Delamare and Bernard Guineau. A small book by the Discoveries Series, Henry N. Abrams Publisher. A lot of information on color, history etc.
None of the above books are on color theory.