A physicist by training, Philippe Renaud has devoted his career to exploring the infinitely small and turning it into technologies capable of acting on living systems. Now Professor Emeritus at EPFL, he pioneered research at the interface of microtechnology, biology and medicine, notably in BioMEMS, nanofluidics and bioelectronics. Following positions at Berkeley, IBM Research and CSEM, he joined EPFL in 1994 and became a full professor in 1997. He also played a major role in developing the School's micro- and nanofabrication infrastructure. His career illustrates that essential passage from science to technology: understanding reality at ever finer scales, then turning that understanding into tools that can measure, diagnose and intervene. His attention is on where disciplines converge, and on the often invisible technologies that profoundly reshape what we are able to do.