This talks describes the Buddha's realization that all things arise and pass away because of causes and conditions. He saw specifically how suffering/dukkha came to be. Once he understood the causes of the arising of suffering, he was able to "reverse engineer" the process, and see how suffering could be brought to an end. He specifically pointed to the vedana (feeling tone) of experience as a specific arising to relate to wisely. On a larger scale, his teachings on the 8 Fold Path to end the clinging which causes dukkha to arise.