This text provides an introduction to nonequilibrium statistical mechanics. It stresses fundamental concepts and the latest methods, rather than individual applications, and will be of interest to advanced students and re- searchers.

1. Brownian Motion.- 1.1 Brownian Motion as a Stochastic Process.- 1.2 The Central Limit Theorem and Brownian Motion.- 1.3 The Langevin Equation and Harmonic Analysis.- 1.4 Gaussian Processes.- 1.5 Brownian Motion Modeled by a Gaussian Process.- 1.6 The Fluctuation-Dissipation Theorem.- 2. Physical Processes as Stochastic Processes.- 2.1 Random Frequency Modulation.- 2.2 Brownian Motion Revisited.- 2.3 Markovian Processes.- 2.4 Fokker-Planck Equation.- 2.5 Contraction of Information. Projected Processes.- 2.6 Derivation of Master Equations.- 2.7 Brownian Motion of a Quantal System.- 2.8 Boltzmann Equation.- 2.9 Generalized Langevin Equation and the Damping Theory.- 3. Relaxation and Resonance Absorption.- 3.1 Linear Irreversible Processes.- 3.2 Complex Admittance.- 3.3 Debye Relaxation.- 3.4 Resonance Absorption.- 3.5 Wave Number-Dependent Complex Admittance.- 3.6 Dispersion Relations.- 3.7 Sum Rules and Interpolation Formulas.- 4. Statistical Mechanics of Linear Response.- 4.1 Static Response to External Force.- 4.2 Dynamic Response to External Force.- 4.3 Symmetry and the Dispersion Relations.- 4.4 Fluctuation and Dissipation Theorem.- 4.5 Density Response, Conduction and Diffusion.- 4.6 Response to Thermal Internal Forces.- 4.7 Some Remarks on the Linear-Response Theory.- 5. Quantum Field Theoretical Methods in Statistical Mechanics.- 5.1 Double-Time Green's Functions.- 5.2 Chain of Equations of Motion and the Decoupling Approximation.- 5.3 Relation to the Kinetic Equation.- 5.4 Single-Particle Green's Function and the Causal Green's Function.- 5.5 Basic Formula for Perturbational Expansion.- 5.6 Temperature Green's function.- 5.7 Diagram Technique.- 5.8 Dyson Equation.- 5.9 Relationship Between the Thermodynamic Potential and the Temperature Green'sFunction.- 5.10 Special Case of the Two-Particle Green's function.- General Bibliography of Textbooks.- References.