The text of this little book is the joint work of Mr Leadbeater and myself; some of it has already appeared as an article in Lucifer (now the Theosophical Review), but the greater part of it is new. The drawing and painting of the Thought-Forms observed by Mr Leadbeater or by myself, or by both of us together, has been done by three friends-Mr John Varley, Mr Prince, and Miss Macfarlane, to each of whom we tender our cordial thanks. To paint in earth's dull colours the forms clothed in the living light of other worlds is a hard and thankless task; so much the more gratitude is due to those who have attempted it. They needed coloured fire, and had only ground earths. We have also to thank Mr F. Bligh Bond for allowing us to use his essay on Vibration Figures, and some of his exquisite drawings. Another friend, who sent us some notes and a few drawings, insists on remaining anonymous, so we can only send our thanks to him with similar anonymity.