Melanie Holmes tells the story of Johnston's journey from a nature-loving Boy Scout to a committed geologist. Blending science with personal detail, Holmes follows Johnston through his encounters with Aleutian volcanoes, his work helping the Portuguese government assess the geothermal power of the Azores, and his dream job as a volcanologist with the U.S. Geological Survey. Interviews and personal writings reveal what a friend called “the most unjaded person I ever met,” an imperfect but kind and intelligent young scientist passionately in love with his life and work and determined to make a difference.