Walter Rauschenbusch (October 4, 1861 – July 25, 1918), the son of a German Lutheran theologian and professor, became the primary American theologian of the Social Gospel movement of the first two decades of the Twentieth Century. While a number of prominent ministers of the day became involved in the movement’s mission to meet social needs through the ministrations of the institutional Church, Rauschenbusch gave this special emphasis a theology, legitimizing it in mainstream American Protestantism. Adherents of the movement believed that many individuals could only leave sinful lifestyles and habits if they were extracted from the social and economic situations that had driven them into sin in the first place. Conversion and life in the Church therefore had to offer something better than sin and addictive habits, as well as alleviate the suffering that drove men to such despair. As a result of this reasoning, individual salvation was important, but considered secondary to social reform, which would convert multitudes into God’s kingdom as the government and economic institutions themselves taught men and women of brotherly love. Salvation of the individual, then, stood as an important byproduct of working for a literal kingdom of God on earth. Working for social improvement, the Kingdom of God on earth, then, was the thrust of the Social Gospel movement. In Rauschenbusch’s words, the Kingdom of God “is not a matter of getting individuals to heaven, but of transforming the life on earth into the harmony of heaven.” Rauschenbusch’s work influenced, among others, Martin Luther King, Jr., and Archbishop Desmond Tutu.

Washington Gladden (February 11, 1836 – July 2, 1918) was a leading American Congregational church pastor and early leader of the Social Gospel movement. He was a leading member of the Progressive Movement, serving for two years as a member of the Columbus, Ohio, City Council and campaigning against Boss Tweed as acting editor of the New York Independent. Gladden was probably the first leading U.S. religious figure to support unionization of the workforce; he also opposed racial segregation. He was a prolific writer, with 40 books to his credit, as well as a number of hymns. He is credited with having written a number of hymns including O Master, Let Me Walk With Thee.

Jacob August Riis (May 3, 1849 – May 26, 1914), was a Danish American social reformer, muckraking journalist and social documentary photographer. He is known for his dedication to using his photographic and journalistic talents to help the impoverished in New York City, which was the subject of most of his prolific writings and photography. He helped with the implementation of “model tenements” in New York with the help of humanitarian Lawrence Veiller. As one of the most prominent proponents of the newly practicable flash, he is considered a pioneer in photography.

(From Wikipedia and other sources.)