The Church of Christ, Scientist was founed in 1879, in Boston, Massachusetts, U.S. by Mary Baker Eddy, the author of its groundbreaking book, Science and Health with Key to the Scriptures, which offers a unique interpretation of Christian faith. Christian Science teaches that the reality of God denies the reality of sin, sickness, death and the material world. Accounts of miraculous healing are common within the church, and adherents often refuse traditional medical treatments. The church, headquartered in Boston, with branches around the world, currently has a membership estimated at 100,000 to 400,000.