This first link is to a website called The Dimensions Of Colour by David Briggs that is probably the ultimate resource in understanding the technical nature of the principles of color in a comprehensive fact filled manner with outstanding color illustrations.
Index Of The Dimensions Of Colour with links
Part 1: Introduction Starting with Colours in Space.
Part 2: Basics of Light and Shade
Part 3: Some Basics of Colour Vision
Part 4: Additive Colour Mixing
Part 5: Subtractive Colour Mixing
Part 6: Colour Mixing with Paint
Part 7: Hue
Part 8: Lightness and Chroma
Part 9: Brightness and Saturation
Part10: Principles of Colour for Painters
The above information is very detailed and will take you some time to get through, if you want to start off with something a bit less detailed, visit the
Free Color Painting Lessons by Richard Robinson.
Below are some book titles on color theory you might be interested in.
Colour: A Handbook of the Theory of Colour by George Henry Hurst
Goethe's Theory of Colours by Johann Wolfgang Von Goethe
Colour Dynamics Workbook Step by Step Guide to Water Colour Painting by Angela Lord
Theory of Colours by the MIT Press
If you find any other useful information on color theory, please comment and I will update this post, take a look at the link, and post it into this resource.