This lecture explores the importance of computational chemistry in understanding and improving the Olefin Metathesis reaction. It covers the challenges faced in experimental chemistry due to the complexity of species involved. The presentation delves into the electronic structure, solvation, and dynamics of the reaction, emphasizing the role of theory and simulation in predicting and optimizing outcomes. The lecture also highlights the significant contributions of Yves Chauvin, Robert H. Grubbs, and Richard R. Schrock, who were awarded the 2005 Nobel Prize in Chemistry for their work on Olefin Metathesis.