E. A. Brunner, or Emil A. Brunner, was a Swiss theologian known for his contributions to Protestant theology in the 20th century. He was a prominent figure in the neo-orthodox movement, which emphasized the importance of divine revelation and the authority of Scripture. Brunner's works often focused on the relationship between faith and reason, as well as the nature of God and humanity. Brunner is best known for his book, The Mediator, where he explores the concept of Jesus Christ as the central figure in understanding God's relationship with humanity. His ideas were influential in shaping modern Christian thought and continue to be studied in theological circles today.