The article discusses the physics of spin ice materials, which are frustrated magnetic systems where the disorder of magnetic moments at low temperatures is analogous to the proton disorder in water ice. Spin ice materials, such as Ho2Ti2O7 and Dy2Ti2O7, exhibit a disordered ground state with macroscopic degeneracy, characterized by the "two in - two out" configuration of spins. The discovery of spin ice was initially based on the analogy between the statistical mechanics of cubic ice and the behavior of magnetic moments in these materials. Experimental and theoretical studies have confirmed the spin ice state in these materials, with specific heat measurements providing evidence for the macroscopic degeneracy. The article also explores the role of dipolar interactions in stabilizing the spin ice state, despite the presence of antiferromagnetic exchange interactions. Numerical simulations using the Ewald summation method have shown that long-range dipolar interactions can restore the ice-rules degeneracy, leading to a disordered spin ice state. The article concludes by discussing open issues and future research directions, including the true ground state, field-dependent behavior, dynamics, and the effects of dilution and related materials.The article discusses the physics of spin ice materials, which are frustrated magnetic systems where the disorder of magnetic moments at low temperatures is analogous to the proton disorder in water ice. Spin ice materials, such as Ho2Ti2O7 and Dy2Ti2O7, exhibit a disordered ground state with macroscopic degeneracy, characterized by the "two in - two out" configuration of spins. The discovery of spin ice was initially based on the analogy between the statistical mechanics of cubic ice and the behavior of magnetic moments in these materials. Experimental and theoretical studies have confirmed the spin ice state in these materials, with specific heat measurements providing evidence for the macroscopic degeneracy. The article also explores the role of dipolar interactions in stabilizing the spin ice state, despite the presence of antiferromagnetic exchange interactions. Numerical simulations using the Ewald summation method have shown that long-range dipolar interactions can restore the ice-rules degeneracy, leading to a disordered spin ice state. The article concludes by discussing open issues and future research directions, including the true ground state, field-dependent behavior, dynamics, and the effects of dilution and related materials.