Hapgood spent ten years working with New England medium Elwood Babbitt (1921-2001), attempting to make contact with notable figures from the past. Babbitt, a retired carpenter and World War II veteran, had studied trance mediumship at Edgar Cayce's Association for Research and Enlightenment. Hapgood audiotaped and transcribed a number of Babbitt's trance lectures which purported to come from Jesus, Albert Einstein, Mark Twain, and the Hindu god Vishnu, using the material to publish his final three books:Voices of Spirit, Through the Psychic Experience of Elwood Babbitt (1975), Talks with Christ and His Teachers Through the Psychic Gift of Elwood Babbitt (1981), and The God Within: a Testament of Vishnu, a Handbook for the Spiritual Renaissance (1982).