The document discusses the history and development of the concept of sustainable development from its origins to modern issues. It begins by outlining how unsustainable human actions like pollution and resource depletion led to the need for a new approach balancing environmental and economic concerns. The concept of sustainable development is defined as having three pillars - environmental, social, and economic sustainability. It also discusses key milestones like the United Nations' definition and the Millennium Development Goals in shaping the current understanding of sustainable development and the ongoing challenges of balancing the three pillars.