In this book, we have, as the object, to discuss under the title : Historical Development of Classical Physico-Mathematics, after studying our thesis : Historical Development of Classical Fluid Dynamics, which includes the theoretical formulation of the microscopically-descriptive hydrodynamical equations, the gas equation, above all, the Navier-Stokes equations. The contents of current book consist of the following six parts entitled with : (Part 1) The Theories of Mathematical Physics in Classical Fluid Dynamics. (Part 2) The Definite Integral by Euler, Lagrange and Laplace from the Viewpoint of Poisson. (Part 3) Confusion on Continuum and Unity in Mathematics. (Part 4) The Wave Equations as the Model of the Schrödinger Equations. (Part 5) The Earlier Toil and Moil in Proving on the Describability of Trigonometric Series. (Part 6) La Valeur Particulière and the Eigenvalue. We introduce French and German originals, which are important evidences for the historical fact. The word 'Physico-Mathematics' in title owes to Poisson's introduction of life rival, Fourier : by the number and the variety of the problems, this theory becomes then a new branch of 'Physico-Mathematics'.