If you are interested in the theory design and if you can find them (no, they're not the A-Team, just maybe out of print), have a look at "Design and Form" and

If you are interested in the theory design and if you can find them (no, they're not the A-Team, just maybe out of print), have a look at "Design and Form" and "The Elements of Colour" both by Johannes Itten and "Principles of Form and Design" by Wucious Wong.