Thought-Forms (1901) by Annie Besant and C.W. Leadbeater
“We have often heard it said that thoughts are things, and there are many among us who are persuaded of the truth of this statement. Yet very few of us have any clear idea as to what kind of thing a thought is, and the object of this little book is to help us to conceive this.”
Thought-Forms is an influential 1901 Theosophist book that works from this premise that “thoughts are things.” The authors propose that the production of “thought-forms” are guided by the following principles:
1. Quality of thought determines color.
2. Nature of thought determines form.
3. Definiteness of thought determines clearness of outline.
The text details the meaning of the colors and shapes evoked by various emotions and states. The above image, for example, is a form generated during meditation which represents “An Aspiration to Enfold All.” The full illustrated text is available at the link below.