Myrtle Fillmore (1845-1931) was an American author and co-founder of the Unity Church, a spiritual movement that emphasizes positive thinking and healing. Along with her husband, Charles Fillmore, she played a significant role in developing the church's teachings, which focus on the power of the mind and the importance of spiritual growth. Myrtle Fillmore is best known for her book, Healing Letters, where she shared her insights on health and spirituality. Her work contributed to the New Thought movement, which promotes the idea that thoughts can influence physical well-being and overall life experiences.