This lecture explores the demographic transition using the Sweden model as a case study, covering topics such as high mortality and fertility, declining mortality due to public health advancements, lagged fertility decline, and the impact on population growth. It also delves into the concept of demographic dividend, age structure changes, and the worldwide expansion of higher education. The presentation discusses the implications of demographic and economic imbalances on international migration, the challenges of population ageing in Europe, and the importance of understanding population pyramids for sustainable development.