Book excerpt: When the size of a machine approaches the nanometer scale, thermal fluctuations become large compared to the energies that drive the motor. The control of motion at the nanoscale therefore requires physical understanding and technical approaches that are fundamentally different from those that are successful at the macroscale. This volume provides an introduction to the state-of-the-art of controlled nanoscale motion in biological and artificial systems. Topics include the control and function of protein motors, the physics of non-equilibrium Brownian motion, and the physics and fabrication of synthetic molecular motors. The chapters in this book are based on selected contributions on the 2005 Nobel Symposium to Controlled Nanoscale Motion and are written by leading experts in their fields.