Systems build upon nano-devices are widely spread in computers, transportation or healthcare equipments. These systems usually involve a huge number of devices, leading to high complexity structures and hardly predictable behaviours. This course provides basic knowledge and tools to study and design such systems. This course provides concepts and tools for the description, the analysis, the design, the optimisation and the validation of such systems at multiple scales. Many examples are used, with a special highlight on digital systems. This course is built upon case studies, practicals and labs. It intends to provide basics engineering skills to be able to interact with product engineers or to manage teams in a system R&D environment.