The Dark Side Sourcebook

From the back cover: If only you knew the power of the dark side... the Force is an all-encompassing energy field generated by all living things. It binds the galaxy together, bringing balance through its two sides. While the light side promotes knowledge and peace, the Force also has a dark side. Anger, fear, and aggression emanate from the dark side, providing a corrupting power to those willing to draw on its destructive nature.