Reprint of The new paradigm of economic complexity

•Economic complexity offers a potentially powerful paradigm to understand key societal issues and challenges of our time.•This brief introduction to economic complexity summarizes key theoretical foundations and principles of economic complexity.•It also reviews the tools and metrics developed in the economic complexity literature that exploit information encoded in the structure of the economy to find new empirical patterns.•It finally aims is to highlight the insights from economic complexity to improve political decision-making.