From programmable microbes to human-machine symbiosis, DARPA’s Biological Technologies Office is expanding the concept of technology and redefining how we interact with and use biology. No longer limited to traditional sensorimotor restoration or therapeutic autonomic modulation, DARPA is developing neurotechnologies that are crossing into applications that stand to overcome current limitations in human performance. Meanwhile, rapid democratization of gene synthesis and editing techniques is bringing engineered biology to the fore on a global scale, and with it a demand for tools that can ensure that any future deployments of these technologies are safe. BTO is addressing the growing need for these and other biosecurity tools to enable aggressive but responsible development and adoption of new biotechnologies—through the design, for example, of such white hat strategies as countermeasures to reduce the risk of unintended consequences and tools to recall genes from open environments. This talk will provide an overview of emerging neuro- and synthetic-biology technologies under development at DARPA, identify strategies for continued responsible development, and reveal relevant possibilities, probabilities, and vulnerabilities.