Christian D. Larson was an outstanding and highly influential early New Thought leader and teacher as well as a prolific writer of New Thought books who believed that people have tremendous latent powers, which could be harnessed for success with the proper attitude.
Hilarious in that its seriousness about things we know are completely false (phrenology) coupled with just basic common sense about health (get plenty of rest to think better) rounded out by a wonderful illustration of the various sections of your brain including your eyes which govern specific types of thought, it’s an insight into the prescience attitude we can still see today, albeit without the excuse of not knowing.