They are a cult that uses extra-biblical books to maintain their beliefs. They are not in the realm of Biblical Christianity yet pose as a church just like mormons, jehovah witnesses, etc
Christian Science is a set of beliefs and practices belonging to the metaphysical family of new religious movements.[n 2] It was developed in 19th-century New England by Mary Baker Eddy, who argued in her book Science and Health (1875) that sickness is an illusion that can be corrected by prayer alone. The book became Christian Science's central text, along with the Bible, and by 2001 had sold over nine million copies.
Eddy and 26 followers were granted a charter in 1879 to found the Church of Christ, Scientist, and in 1894 the Mother Church, The First Church of Christ, Scientist, was built in Boston, Massachusetts. Christian Science became the fastest growing religion in the United States, with nearly 270,000 members by 1936, a figure that had declined by 1990 to just over 100,000. The church is known for its newspaper, the Christian Science Monitor, which won seven Pulitzer Prizes between 1950 and 2002, and for its Reading Rooms, which are open to the public in around 1,200 cities.
SI Moderator - Greg Gordon