"Varieties of Democracy, or "V-Dem, " is a global research project producing new measures of hundreds of attributes of democracy as far back as 1789 for many countries, and for almost all countries around the world from 1900 to the present. This book is a reference guide for anyone who wants to use V-Dem data wisely. It provides full information about the concepts that the data measure, what we know about the validity and reliability of the data, what it reveals about the structure of democracy and the general trends in democratization over the past 229 years, as well as why this explosion of information is likely to raise the standards for causal inferences in democratization research. The V-Dem team and others are already producing a series of publications and papers leveraging the distinctive strengths of these new data, so this book also calls attention to some of those first fruits"--