Machines in engineering use mostly hard materials, whereas machines in nature are often soft.  This difference has been an inspiration for the nascent field of soft machines.  What does softness impart to the life of animals and plants?   Softness enables deformation, and deformation provides functions.  Familiar examples include the beating of the heart, the sound shaped by the vocal folds, and the flapping of the wing.  In soft machines, the large deformation enable soft materials to behave as transducers, connecting multiple stimuli to multiple functions.  How do molecular processes enable new classes of actuators and sensors?  How efficiently can materials convert information from one form to another?  These questions are stimulating new and exciting developments at the interface between science and engineering.  This talk highlights the behavior of soft materials that enables the creation of soft machines.  Examples include highly stretchable and transparent devices that mimic the functions of muscles, skins and axons.