Timothy James Keller (September 23, 1950 – May 19, 2023) was an American Presbyterian pastor, preacher, theologian, and Christian apologist.

[16] He also served on the faculty of Westminster Theological Seminary in Philadelphia, where he and his wife Kathy Keller were involved in urban ministry.

The book, The Reason for God, was based on common objections to the Christian faith heard during his ministry in New York City.

In his preaching, "he hardly shrinks from difficult Christian truths, [but] he sounds different from many of the shrill evangelical voices in the public sphere.

His mentoring of younger church leaders, such as Scott Sauls[23] in Nashville and Steve Chong[24] in Sydney, increased his influence globally.

[25] Keller shunned the label "evangelical" because of its political and fundamentalist connotation, preferring to call himself orthodox because "he believes in the importance of personal conversion or being 'born again,' and the full authority of the Bible.

Keller's preaching and writing in his apologetics is characterized by a respectful orientation towards an educated and skeptical audience outside the faith.

[31] Keller's major influences in apologetics included C. S. Lewis, Cornelius Van Til,[32] John Stott, Alvin Plantinga, N.T Wright,[33] and Miroslav Volf.

[37][38] Keller criticized the evangelical alliance with Republicans and argued that Christianity is a much broader global movement that agrees with some liberal and some conservative issues, and critiqued them both.

[39][40] He argued for giving to charitable causes and caring for the needs of the poor, based on biblical texts such as the Torah and the parable of the Good Samaritan.

[41][42] Attributed partly to his congregation of upwardly mobile Manhattanites, Keller was a leader in applying Christian theology to secular vocations such as business, art and entrepreneurship.

[30][47] While at Westminster Theological Seminary, Keller was mentored by Harvie Conn, an early advocate of ministry in urban centers.