As alarm over global warming spreads, a radical idea is gaining momentum. Forget cuts in greenhouse gas emissions, some scientists argue. Instead, bounce sunlight back into space by pumping reflective nanoparticles into the atmosphere. Launch mirrors into orbit around the Earth. Make clouds thicker and brighter to create a 'planetary thermostat.' These ideas might sound like science fiction, but in fact they are part of a very old story. For more than a century, scientists, soldiers, and charlatans have tried to manipulate weather and climate, and like them, today's climate engineers wildly exaggerate what is possible. Scarcely considering the political, military, and ethical implications of managing the world's climate, these individuals hatch schemes with potential consequences that far outweigh anything their predecessors might have faced. Showing what can happen when fixing the sky becomes a dangerous experiment in pseudoscience, James Rodger Fleming traces the tragicomic history