Our ability to speak is what made us the planet's dominant species, argues John Colapinto, and here he guides us from the voice's beginnings in lungfish millions of years ago to its culmination in the talents of Pavoratti and Martin Luther King Jr.—and each of us, every day. Along the way, he travels up the Amazon to meet the Piraha, a tribe with a musical language; to Harvard, to see how professional voices are helped and healed; and out on the campaign trail, where demagogues wield their voices as weapons.