In this final chapter, we explore several phenomena related to the evolution and formation of galaxies, drawing on the knowledge discussed throughout this work. We begin with the growth of stellar mass in galaxies, using a phenomenology-based approach proposed by Drory & Alvarez (2008). Next, we address the evolution of star formation in galaxies, focusing on those visible in optical/ultraviolet wavelengths and those obscured by dust. We then delve into the physics of galaxy formation. In comparison to the dark matter halo mass function, the stellar mass function of galaxies exhibits a significant deficit at both the high- and low-mass ends. The absence of galaxies with \(\mathcal{M}_* > 10^{12}\;[\mathcal{M}_\odot ]\) has been attributed to the cooling time argument. However, further investigation indicates that an additional mechanism is needed to halt star formation in the central galaxies of clusters. Feedback from active galactic nuclei (AGN) is considered a likely explanation. Meanwhile, the small number of low-mass galaxies is explained by supernova feedback. Finally, we briefly introduce a few open questions in the concluding remarks.