This document discusses the different waves of democratization that have occurred globally since the 1820s. It outlines the key features and timeline of the first wave from 1828-1926, which saw the adoption of universal suffrage in many countries beginning with the US in 1828. It then describes the reverse wave from 1922-1942 that led to the rise of authoritarian regimes in places like Germany, Italy and Spain. The second wave from 1943-1962 and its reverse from 1958-1972 which saw both new democracies and military interventions are also examined. Finally, it analyzes the ongoing third wave since 1974 and factors like economic development and culture that influence democratization.