In a riveting investigation of the science and ecology of wildfires, journalist M.R. O'Connor ventures into some of the oldest, most beautiful, and remote forests in North America to explore the powerful and ancient relationship between trees, fires, and humans. Along the way, she describes revelatory research in the fields of paleobotany and climate science to show how the world's forests have been shaped by fire for hundreds of millions of years. She also reports on the compelling archeological evidence emerging from the field of ethnoecology that proves how, until very recently, humans were instigators of forest fires, actively molding and influencing the ecosystems around them by inserting themselves into the loop of a natural biological process to start "good fires." As she weaves together first-hand reportage with research and cultural insights, O'Connor also embeds on firelines alongside firefighters and "pyrotechnicians." These highly trained individuals are resurrecting the practice of prescribed burning in an effort to sustain fire-dependent forest ecologies and prevent the catastrophic wildfires that are increasing in frequency and intensity as a result of global warming. Hailing from diverse backgrounds including state and federal agencies, scientific laboratories, and private lands and tribal nations, these fire starters are undertaking a radical and often controversial effort to promote, protect, and expand the responsible use of fire to restore ecological health to landscapes. At the heart of Ignition is a discussion about risk and how our relationship to it as a society will determine our potential to survive the onslaught of climate change.