Is extinction forever? Efforts are under way to use gene editing and other tools of biotechnology to “recreate” extinct species such as the woolly mammoth and the passenger pigeon. Could such “de-extinction” initiatives aid conservation by reviving species lost to habitat destruction and climate change? Or are they more likely to hinder conservation? What should the guiding ideals of conservation be in a new age of biotechnology? These are some of the questions addressed in a new report.