Kondratiev waves are long-term economic cycles that last approximately 50 to 60 years. Named after Russian economist Nikolai Kondratiev, these waves are characterized by periods of economic growth followed by downturns. They are believed to be driven by technological innovations, shifts in consumer behavior, and changes in production methods. These waves typically consist of four phases: expansion, crisis, recession, and recovery. Each phase reflects changes in investment, employment, and overall economic activity. Understanding Kondratiev waves can help economists and policymakers anticipate long-term trends and make informed decisions about economic strategies.