The paper by Kormendy and Kennicutt reviews the secular evolution of disk galaxies, focusing on the formation of pseudobulges. Pseudobulges are dense central components in disk galaxies that resemble classical bulges formed by mergers but are built up slowly from disk gas. The authors discuss how bars rearrange disk gas into outer and inner rings, with gas transported to small radii reaching high densities and leading to star formation. Observations show that many pseudobulges have dense central concentrations of gas and star formation, supporting the theory that they form from disk material. The paper also explores the characteristics of pseudobulges, such as their flatter shapes, large ratios of ordered to random velocities, small velocity dispersions, spiral structure, and starbursts. The formation timescales of pseudobulges are estimated to be reasonable, on the order of a few billion years. The authors conclude that secular evolution, driven by processes like bar and oval distortions, is a significant component of galaxy evolution, complementing hierarchical clustering and mergers. They emphasize that every galaxy is dynamically evolving, and the classification of bulges as either classical or pseudobulges should be based on their physical origins.The paper by Kormendy and Kennicutt reviews the secular evolution of disk galaxies, focusing on the formation of pseudobulges. Pseudobulges are dense central components in disk galaxies that resemble classical bulges formed by mergers but are built up slowly from disk gas. The authors discuss how bars rearrange disk gas into outer and inner rings, with gas transported to small radii reaching high densities and leading to star formation. Observations show that many pseudobulges have dense central concentrations of gas and star formation, supporting the theory that they form from disk material. The paper also explores the characteristics of pseudobulges, such as their flatter shapes, large ratios of ordered to random velocities, small velocity dispersions, spiral structure, and starbursts. The formation timescales of pseudobulges are estimated to be reasonable, on the order of a few billion years. The authors conclude that secular evolution, driven by processes like bar and oval distortions, is a significant component of galaxy evolution, complementing hierarchical clustering and mergers. They emphasize that every galaxy is dynamically evolving, and the classification of bulges as either classical or pseudobulges should be based on their physical origins.