The driving goal behind our work is to make large groups of small robots truly useful as tools in industrial, commercial, and personal settings, for applications like precision agriulcture, urban sensing, and search and rescue. This means not only overcoming the extreme resource constraints imposed by their scale, but also delivering capabilities that are wholly unique. Sometimes we look to nature for inspiration, like in the design of multifunctional components for acoustic communication; often we look beyond it, like in the creation of silent, solid-state atmospheric ion thrusters for flight. In all cases, energy and payload constraints demand systems designed from the ground up, tightly integrated and at the bleeding edge of possibility.