I.- Hypergeometric Differential Equations.- General Theory of Differential Equations I.- The Riemann and Riemann-Hilbert Problems.- Schwarzian Derivatives I.- The Gauss-Schwarz Theory for Hypergeometric Differential Equations.- II.- Hypergeometric Differential Equations in Several Variables.- The General Theory of Differential Equations.- Schwarzian Derivatives II.- The Riemann and Riemann-Hilbert Problems II.- The Gauss-Schwarz Theory in Two Variables.- Reflection Groups.- Toward Finding New Differential Equations.