ИСТИНА

This survey is motivated by an amazing analogy between the physics of common water ice and the new eld of magnetism called now spin ice physics. Its main goal is to show how fundamental concepts of water ice physics work or could work in magnetism. More specically we discuss such peculiar concepts of ice physics as ice rules, exponential degeneracy of ground state, classical quasiparticles, dynamics of protons, correlation functions, and entropy production eects. We also discuss the dierences between water and spin ice, and some promising areas of researches.