Charles Finney was a prominent American preacher and theologian in the 19th century, known for his role in the Second Great Awakening. He emphasized personal conversion and the importance of individual faith, often conducting revival meetings that attracted large crowds. His innovative methods included the use of emotional appeals and public invitations for people to accept Christianity. Finney also contributed to the development of modern evangelism and was a strong advocate for social reforms, including the abolition of slavery and women's rights. His writings and sermons influenced many, making him a key figure in the history of American Protestantism.