An study on the nature and power of thoughts. The authors state that thoughts have two effects: "a radiating vibration and a floating form. " Thought forms are divided into three classes: That which takes the image of the thinker. That which takes the image of some material object. That which takes a form entirely its own, expressing its inherent qualities in the matter which it draws round it. The effect of music, emotions, and colors on thought forms is also studied in the book.