The increasing volume and nature of big datasets in business, economics, social and political sciences call for more complex and sophisticated mathematical and data mining tools. The complex systems monitored by big databases are successfully described in terms of networks. In this course we will present and discuss mathematical and data mining tools used to characterize large empirical or model networks. Large datasets will be computationally investigated and the limits of the used algorithms will be discussed. The assessment of the statistical validity of the observed results will be analyzed and, when possible, quantitatively evaluated. Besides the mathematical theory, the course will have a practical approach with homework and the development of a project. The project will involve data analysis and computer simulations in Python (with e.g. Jupyter notebooks).