The Principles of Light and Color is an unchanged, high-quality reprint of the original edition of 1878. Hansebooks is editor of the literature on different topic areas such as research and science, travel and expeditions, cooking and nutrition, medicine, and other genres. As a publisher we focus on the preservation of historical literature. Many works of historical writers and scientists are available today as antiques only. Hansebooks newly publishes these books and contributes to the preservation of literature which has become rare and historical knowledge for the future.

The idea of light as an integral part of all life and creation was evident since the beginning of time. From the very first sunrise, to the daily sunsets of the present, we continue to be awed by the beauty, power, life creating and life sustaining properties and emanations of light. The rainbow, truly a miracle of nature, confirms not only the importance of color, but specifically those portions of the spectrum for which the human organism is attuned. During the early 1920s, science had begun to speculate that the power of light was primarily transmitted to the core of the human organism by the organ of sight - the eyes. It was in that same period of time that one man, Dr. Harry Riley Spitler, theorized in great detail the role of the eyes in phototransduction, as well as the role of light and color in total organismic function and development. Most of his work has been scientifically validated, and represents the foundation of one of today's most advanced approaches to phototherapy: syntonics. Syntonics, utilized clinically for more than sixty years within the field of Optometry, is that branch of ocular science dealing with the application of selected visible light frequencies through the eyes. This ocular application of light has been utilized with great success in the treatment of various visual dysfunctions associated with strabismus, amblyopia, accomodative/convergence problems, visual field constrictions, head trauma, and visually related learning problems. The results of these relatively short term treatments usually yield significant improvements in visual skills, visual field size, memory, general performance, behavior, mood, and academic achievement. Now we notice that phototherapy is becoming an increasingly prevalent therapeutic tool within the medical community. We are proud to be part of the lineage of vision specialists who discovered, researched and consistently cultivated the science of ocular phototherapy: Syntonics.

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