There are several insightful books, including:
Ode to Grapefruit: How James Earl Jones Found His Voice
JAMES EARL JONES: THE BIOGRAPHY AND STORY OF A STAR WHO HOLDS THE GUINNESS WORLD RECORD FOR "MOST WORDS RECORDED BY A MALE VOICE ACTOR"
ECHOES OF GREATNESS: THE JAMES EARL JONES MEMOIR
James Earl Jones Reads the Bible: The King James Version of the New Testament