From publisher blurb:
Colours of Magic: Green Fifth Edition Update
A Spectrum Shift: Chromatic Arcana Product
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.
Indigo is the colour of the mind. It is a deeper shade of Blue; where blue looks externally in the universe for ways to make order and gain control, Indigo looks within, seeking first and foremost order and control of the mind.
Those with mastery over Indigo magic can control others with a thought, bring oblivion upon their enemies and manipulate the very fabric of dreams.
Included in this product:
3 new Class options, one for each of Cleric (Cerebrant), Sorcerer (Dreamspawn) and Wizard (Skeptomancer)
a reclassification of one eleventh of the spells of the players handbook