Nonlinear Phenomena in Physics

It was almost four hundred years ago that Galileo wrote in Il Saggiatore that the "Book of Nature is written in mathema ti ca 1 characters". Thi s sentence, i nspi red at the dawn of physics has proved with the passage of time to contain a deep truth and also a warning: in order to understand Nature, first we must learn to read mathema­ tical characters. Indeed, writing physical law in such charac...