Donald McGavran was an influential American missionary and church growth expert, known for his work in the mid-20th century. He emphasized the importance of reaching specific cultural and social groups, which he termed "people movements." His ideas significantly shaped modern evangelism and church planting strategies. McGavran founded the School of World Mission at Fuller Theological Seminary in California, where he trained many leaders in effective church growth methods. His book, The Bridges of God, outlined his theories and practices, making a lasting impact on how churches approach outreach and community engagement.