It has been more than 50 years since electronic computers came into existence. They were built for one reason only - to solve scientific problems. From that time till the present, scientific problems have always been the driving force in the development of faster and more powerful computers. Within this area of Scientific Computation, the approximate solution of differential equations remains an area of special challenge. Differential equations can usually not be solved analytically and there is no choice but to resort to numerical methods, which traditionally has meant either linear multi step methods or Runge–Kutta methods. However, these traditional methods are special cases within the larger class of "General Linear Methods". Today I will look briefly at the history of numerical methods for differential equations and then some particular questions concerning the theory of general linear methods and some aspects of their practical implementation.