An artificial third arm that assists my actions with little cognitive effort and that can seamlessly be controlled concurrently and independently to my natural arms is a popular phantasm in science fiction. If to come true, however, this vision would revolutionise human life by enabling people to accomplish tasks that are sheer impossible with their natural limbs alone. Surgeons could become able to control additional surgical devices, a computer mouse commanded simultaneously to my fingers would enable me to operate a maps application on my phone while dragging my luggage, etc. The NIMA project follows a concrete and novel concept to make this vision a reality, by exploiting the redundancy of the motor system on different levels for controlling additional degrees-of-freedom of supernumerary limbs, devices or computers independently from movements of the natural limbs. We have formed a team of leading experts in neuroscience, neurotechnology, human-machine interfaces, robotics, and ethics, to accomplish the following objectives: 1) Pushing the borders of technology by creating non-invasive interfaces with multimodal sensory feedback that will allow effortless control of multiple limbs or objects, as well as a wearable supernumerary robotic limb. 2) Understanding the cognitive and neural mechanisms underlying movement augmentation, how it can be functionally embodied and how this can be facilitated by multimodal feedback, by combining neuromodulation, computational modelling and behavioural experiments. 3) Applying movement augmentation to extend human capacities and preparing the ground for exploitation, using three relevant testbeds: i) manipulation with a wearable supernumerary robotic arm and the two hands, ii) assistance in surgical manipulation to extend surgeon capabilities and autonomy, iii) 3-hands computer interface. 4) Evaluating the ethical and safety aspects of movement augmentation.