Armstrongism is a religious movement based on the teachings of Herbert W. Armstrong, who founded the Worldwide Church of God in the 1930s. It emphasizes a unique interpretation of the Bible, focusing on the observance of the Sabbath, the importance of the Old Testament, and the belief in a coming Kingdom of God on Earth. The movement gained popularity through its literature and broadcasts, particularly the program "The World Tomorrow." After Armstrong's death in 1986, the church underwent significant changes, leading to a decline in adherence to his original teachings. Today, various splinter groups continue to promote Armstrong's doctrines.