The formation of stars in galaxies is a central topic in modern astrophysics, but the exact mechanisms controlling the star formation rate and initial mass distribution remain unclear. Traditionally, it was believed that gravity and magnetic fields, along with neutral-ion drift, governed star formation. However, recent observational and numerical studies suggest that supersonic turbulence plays a more significant role than static magnetic fields. This review explores the historical development of theories on star formation, including the classical dynamical theory and the standard theory of magnetostatic support, and presents a new theory based on supersonic turbulence. Numerical models show that supersonic turbulence provides global support but also creates density enhancements that allow local collapse. Efficient, clustered star formation occurs in the absence of turbulence, while inefficient, isolated formation is associated with turbulent support. The theory suggests that star-forming cores are dynamically collapsing, and their accretion rates depend on the surrounding turbulent flow. Molecular clouds are transient features in the turbulent interstellar medium, forming and dissolving over time. The review also discusses the role of supernovae as the dominant driving mechanism in star-forming regions, and the influence of magnetic fields and rotation in other areas. It concludes that the balance between gravity and turbulence controls star formation at both small and galactic scales, with cooling and differential rotation modulating this balance. The review highlights the importance of supersonic turbulence in shaping the structure and evolution of molecular clouds and the distribution of stellar masses.The formation of stars in galaxies is a central topic in modern astrophysics, but the exact mechanisms controlling the star formation rate and initial mass distribution remain unclear. Traditionally, it was believed that gravity and magnetic fields, along with neutral-ion drift, governed star formation. However, recent observational and numerical studies suggest that supersonic turbulence plays a more significant role than static magnetic fields. This review explores the historical development of theories on star formation, including the classical dynamical theory and the standard theory of magnetostatic support, and presents a new theory based on supersonic turbulence. Numerical models show that supersonic turbulence provides global support but also creates density enhancements that allow local collapse. Efficient, clustered star formation occurs in the absence of turbulence, while inefficient, isolated formation is associated with turbulent support. The theory suggests that star-forming cores are dynamically collapsing, and their accretion rates depend on the surrounding turbulent flow. Molecular clouds are transient features in the turbulent interstellar medium, forming and dissolving over time. The review also discusses the role of supernovae as the dominant driving mechanism in star-forming regions, and the influence of magnetic fields and rotation in other areas. It concludes that the balance between gravity and turbulence controls star formation at both small and galactic scales, with cooling and differential rotation modulating this balance. The review highlights the importance of supersonic turbulence in shaping the structure and evolution of molecular clouds and the distribution of stellar masses.