I Physical Chemistry.- Wigner on Physical Chemistry.- On Electrical Phenomena in Sols with Rod-Shaped Particles / Über elektrische Erscheinungen bei Stäbchensolen.- The Lattice Structure of Rhombic Sulfur / Die Gitterstruktur des rhombischen Schwefels.- Formation and Decay of Molecules / Bildung und Zerfall von Molekülen.- On the Interference of Eigenvibrations as a Cause of Energy Fluctuations and Chemical Reactions / Über die Interferenz von Eigenschwingungen als Ursache von Energieschwankungen und chemischer Umsetzungen.- The Statistics of Composite Systems According to the New Quantum Mechanics / Statistik zusammengesetzter Systeme nach der neueren Quanten-Mechanik.- On the Rate Constants of Exchange Reactions / Über die Geschwindigkeitskonstante von Austauschreaktionen.- On Crossing Over Potential Barriers in Chemical Reactions / Über das Überschreiten von Potentialschwellen bei chemischen Reaktionen.- On the Quantum Correction for Thermodynamic Equilibrium.- Contributions to the Theory of the Neutron / Beiträge zur Theorie des Neutrons.- On the Paramagnetic Transition of Para-Ortho-Hydrogen. III / Über die paramagnetische Umwandlung von Para-Orthowasserstoff. III.- On a Modification of the Rayleigh-Schrödinger Perturbation Theory.- Calculation of the Rate of Elementary Reactions of Light and Heavy Hydrogen.- On the Rate of Chemical Reactions.- Calculation of the Rate of Elementary Association Reactions.- The Transition State Method.- Some Quantum-Mechanical Considerations in the Theory of Reactions Involving an Activation Energy.- Some Remarks on the Theory of Reaction Rates.- On the Calculation of the Distribution function.- Electromagnetic Field Expansions in Loss-Free Cavities Excited Through Holes.- The Problem of Multiple Scattering.- Derivations of Onsager's Reciprocal Relations.- Lower Limit for the Energy Derivative of the Scattering Phase Shift.- Review of Collision Theory.- Quantum-Mechanical Distribution Functions Revisited.- Quantum-Mechanical Distribution Functions: Conditions for Uniqueness.- Some Properties of a Non-negative Quantum-Mechanical Distribution function.- Distribution Functions in Physics: Fundamentals.- Manifestations of Bose and Fermi Statistics on the Quantum Distribution Function for Systems of Spin-0 and Spin-1/2 Particles.- Covariant Phase-Space Representation for Harmonic Oscillators.- The General Properties of the Distribution Function and Remarks on its Weakness.- Covariant Phase-Space Representation and Overlapping Distribution Functions.- II Solid State Physiscs.- Wigner on Solid State Physics.- On the Constitution of Metallic Sodium.- On the Constitution of Metallic Sodium. II.- On the Interaction of Electrons in Metals.- Theory of the Work Functions of Monovalent Metals.- On the Possibility of a Metallic Modification of Hydrogen.- On the Structure of Solid Bodies.- Theory of the Brillouin Zones and Symmetry Properties of Wave Functions in Crystals.- On the Constant A in Richardson's Equation.- Effects of the Electron Interaction on the Energy Levels of Electrons in Metals.- Qualitative Theory of the Cohesion in Metals.- Bibliography of Papers on Solid State Physics.- Papers Reprinted in Volume IV.- Papers Related But Reprinted in Other Volumes of The Collected Works.- Papers Related But Not Reprinted in The Collected Works.