Ravi Zacharias is the Founder and President of Ravi Zacharias International Ministries, headquartered in Atlanta, Georgia, with additional offices in Canada, Hong Kong, India, Singapore, the United Kingdom, Austria, South Africa, Spain, and Turkey. Zacharias and his wife, Margie, have three grown children. He is the author of many books, including Can Man Live Without God and Why Jesus?

Dr. Vince Vitale is Director of the Zacharias Institute. He was educated at Princeton University and the University of Oxford, and later taught philosophy of religion as a faculty member at both universities. During his undergraduate studies at Princeton, Dr. Vitale took an unexpected journey that led him to God. Later, while at Oxford, he developed a new response the problem of evil. This response -- termed the Non-Identity Defense -- is discussed in his and Ravi Zacharias's previous book, Why Suffering? He is married to Jo, who also works for RZIM.