Christian Daa Larson was an American New Thought leader and teacher, as well as a prolific author of metaphysical and New Thought books. He is credited by Horatio Dresser as being a founder in the New Thought movement. Many of Larson's books remain in print today, more than 100 years after they were first published, and his writings influenced notable New Thought authors and leaders, including Religious Science founder Ernest Holmes.
Larson was born in Iowa, of Norwegian descent. He attended Iowa State College and a Unitarian theological school in Meadville, Pennsylvania. In his early twenties he became interested in the Mental Science teachings of Helen Wilmans, Henry Wood, Charles Brodie Patterson et al.
In 1898 Larson relocated to Cincinnati, Ohio. In January 1901, he organized the New Thought Temple at his residence at 947 West 17th St. In September 1901 he began to publish Eternal Progress, for several years one of the leading New Thought periodicals, building it to a circulation of over a quarter of a million. Meanwhile, he began his prolific book writing career.
Larson later became honorary president of the International New Thought Alliance and lectured extensively during the 1920s and 1930s. He was a colleague of such notables as William Walker Atkinson, Charles Brodie Patterson, and Home of Truth founder Annie Rix Militz.
Early in the career of Ernest Holmes, Larson's writings so impressed him that he abandoned Mary Baker Eddy's Christian Science textbook Science and Health with Key to the Scriptures for them. Ernest and his brother Fenwicke Holmes took a correspondence course with Larson, and in his biography of his brother, Ernest Holmes: His Life and Times, Fenwicke elaborates on the influence of Larson's thought on Ernest, ranking Larson's The Ideal Made Real with Ralph Waldo Trine's In Tune with the Infinite in its influence over him.
In 1912 Larson published a poem that eventually became the Optimist Creed, which in 1922 was adopted by Optimist International, better known as the Optimist Clubs.