Denmark, Estonia, Finland, Norway, and Sweden participated in the first round of the International Survey of Adults’ Skills. The survey is a product of the Programme for the International Assessment of Adult Competencies (PIAAC) led by the Organisation for Economic Co-operation and Development (OECD). The survey assessed the proficiency in literacy, numeracy, and problem-solving in technology-rich environments of adults aged 16–65. This publication is the product of the Nordic PIAAC Network, consisting of members from all five countries. It concentrates on the comparative results from four Nordic countries and Estonia, forming a Nordic region with many common features. It supplements the series of national and international PIAAC reports by comparing the results from five countries, as well as comparing an aggregate of these countries to other country aggregates. The results published in this book draw on a unique Nordic database, which the Nordic PIAAC Network has produced. The database consists of PIAAC assessment data and background information, supplemented by social, educational, and labour market register data from the five countries.