Wikipedia States: (

Arnold Ehret (1866–1922) was the author of several health and fitness books.
Professor Arnold Ehret, revered as the original father of naturopath and he is considered to be the most important researcher and author regarding the health and preservation of the human body by his followers. These followers, called Ehretists, believe that no other scientist, doctor, dietitian, or author has surpassed Ehret’s work concerning the cause and cure of chronic disease and human illness. Ehret is claimed to have discovered that the human body is an “air-gas engine” that is powered exclusively by oxygen and that a diet consisting of starchless fruits and green-leafy vegetables is the only food fit for human consumption

Here are some books Professor Arnold Ehret wrote.

Arnold - Story of my Life.

Arnold - Mucusless Diet

Arnold - Chronic Constipation

Arnold - Rational Fasting