From Ordinary to Partial Differential Equations 1 Ordinary differential equations 2 Linear elliptic equations 3 Calculus of variations 4 Linear and non linear hyperbolic equations 5 Parabolic equations 6 Fuchsian functions 7 The Riemann function 8 A window on modern theory 9 References This book is addressed to mathematics and physics students who want to develop an interdisciplinary view of mathematics from the age of Riemann Poincaré and Darboux to basic tools of modern mathematics. It enables them to acquire the sensibility necessary for the formulation and solution of difficult problems with an emphasis on concepts rigour and creativity. It consists of eight self contained parts: ordinary differential equations; linear elliptic equations; calculus of variations; linear and non linear hyperbolic equations; parabolic equations; Fuchsian functions and non linear equations; the functional equations of number theory; pseudo differential operators and pseudo differential equations. The author leads readers through the original papers and introduces new concepts with a selection of topics and examples that are of high pedagogical value