From the publisher:

In some worlds, Magic may not be seen as a force in and of itself. In some philosophies, magic can not be classed by types of effect, like Evocation, Illusion or Abjuration. Instead, it might be seen as a result of fundamental aspects of arcane metaphysics.

One such theory holds that all magic is a result of the principles of Colour.

Brown is the colour of the broken earth and chopped wood. Wherever the hand of man (or any other technically minded race) seeks to mould the universe for its own benefit it can be seen. It is concerned with crafting the elements, manipulating the forces of the universe and even bending the dimensions of space.

Those that devote themselves to learning Brown magic can create things out of thin air, travel across space or even dimensions, and create and manipulate fields of force.

The most devoted of these is the Demiurge. They learn to blend magic into the material, and have advantages over other wizards in creating magical items. They gain access to high level magic faster than most other classes.

Included in this product:

3 new Clerical or Mystical domains
a linked reclassification of one twelfth of the spells of the players handbook, with some new spell effects to fit the spells into Chromatic Magic Theory
a whole new character class, the Demiurge. This spellcaster is a maker and user of items, and master of Brown Magic.