My group builds robots the size of microorganisms (10-100 um) with top-down nanofabrication. By perusing sophisticated machines that move, sense, and compute, we hope to achieve two goals. First, we want to develop a physics of living systems that can both describe biology and extend beyond it. Microscopic in size, these robots experience the same physics as their biological counterparts, allowing us to draw comparisons. Yet because our machines are built from the top down, humans can easily measure, control, and comprehend their behavior. We expect the lessons learned designing and building small machines can expand our understanding of living matter, physics, and the relationship between the two. Second, we want to use these robots to engineer the microworld. Biology shows us the power of tiny agents: living matter organizes, grows, heals, and adapts. With microscopic robots that humans can program and control, we see a new, parallel path to technologies that do the same.