Zurek's Einselection & Pointer States — Decoherence destroys superpositions via entanglement with the environment. Only pointer states (eigenstates of the system-environment interaction Hamiltonian) survive: they are dynamically robust. The density matrix ρ(x,x') loses off-diagonal coherences at rate γ|x−x'|², leaving a mixture of localized pointer states. This einselection (environment-induced superselection) explains the quantum-to-classical transition without wavefunction collapse.