The MHD Equations -- Derivation of the MHD Equations -- Multispecies MHD Equations -- One-Fluid Model of Magnetohydrodynamics -- Validity of the One-Fluid Model of Magnetohydrodynamics -- Consequences of the MHD Equations -- Magnetic Flux Conservation -- MHD Equilibrium -- Magnetohydrodynamic Waves -- Compressional Alfvén Waves -- Shear Alfvén Waves -- MHD Equilibria in Fusion Plasmas -- Linear Configurations -- The z-Pinch -- The Screw Pinch -- Toroidal Configurations -- The Tokamak -- Tire Grad-Shafranov Equation -- Circular Cross Section -- Arbitrary Cross Section -- The Straight Field Line Angle -- The Stellarator -- Linear Ideal MHD Stability Analysis -- Linear MHD Stability as an Initial Value Problem -- The Energy Principle of Ideal MHD -- Forms of δW -- The Ideal MHD Energy Principle for the Tokamak -- Current Driven Ideal MHD Modes in a Tokamak -- Expression for δW in Tokamak Ordering -- External Kinks in a Tokamak with β = 0 -- Modes with m = 1 -- Modes with m ≥ 2 -- Internal Kink Modes -- n = 0 Modes: The Vertical Displacement Event (VDE) -- Pressure Driven Modes in a Tokamak -- Localized Interchange Modes in the Screw Pinch -- Localized Pressure Driven Modes in the Tokamak -- Interchange Modes in a Tokamak -- Ballooning Modes -- Combined Pressure and Current Driven Modes: Edge Localized Modes -- ELM Phenomenology -- Linear Stability of the Pedestal -- Non-linear Evolution -- Non-linear Cycles -- Magnitude of the ELM Crash -- Timescale of the ELM Crash -- ELM Control -- Small ELM Regimes -- Active ELM Control -- Combined Pressure and Current Driven Modes: The Ideal β-limit -- Tokamak Operational Scenarios -- External Kink Modes in a Tokamak with Finite β -- The Effect of a Conducting Wall on External Kink Modes -- Ideally Conducting Wall -- Resistive Wall -- The Resistive Wall Mode (RWM) -- Tire Troyon Limit -- Resistive MHD Stability -- Stability of Current Sheets -- Reconnection in the Presence of a Guide Field -- Magnetic Islands in Tokamaks -- The Rutherford Equation -- Current Driven ('classical') Tearing Modes in Tokamaks -- Effect of Tearing Modes on Kinetic Profiles -- Nonlinear Saturation -- Tearing Mode Rotation and Locking -- Rotation of Tearing Modes in Tokamaks -- Locking of Pre-existing Magnetic Islands -- Ab-initio Locked Modes -- Disruptions -- Phenomenology of Disruptions -- The Density Limit -- Consequences of Disruptions -- Thermal Loads -- Mechanical Loads i66 -- Runaway Generation -- Disruption Avoidance and Mitigation -- M=1 Modes beyond Ideal MHD: Sawteeth and Fishbones -- The Sawtooth Instability -- Phenomenology -- Sawtooth Period and Onset Criterion -- Models for the Sawtooth Crash -- The Fishbone Instability -- Tearing Modes in Finite β-Tokamaks -- The Modified Rutherford Equation -- The Neoclassical Tearing Mode (NTM) -- Onset Criteria for NTMs -- Frequently Interrupted Regime (FIR) NTMs -- Control of Resistive MHD Instabilities by External Current Drive -- Basic Properties of Localized Electron Cyclotron Current Drive (ECCD) -- Criteria for Control of Resistive Instabilities -- Control by Changing the Equilibrium Current Density -- Control by Generating Helical Currents -- Sawtooth Control -- Tearing Mode Control