The Production of Low Temperatures Down to Hydrogen Temperature.- Preface.- A. Refrigeration by gas (air) machines.- B. Compressed vapor refrigerating machines.- C. Cooling of gases by Joule-Thomson effect.- D. Theory of gas liquefaction using Joule-Thomson expansion.- E. Practical aspects of gas liquefaction using only Joule-Thomson expansion.- F. Theory of gas liquefaction using isentropic expansion.- G. Practical aspects of gas liquefaction using expansion engines.- H. Liquefaction by isentropic expansion.- I. Heat interchangers and regenerators.- Helium Liquefiers and Carriers.- A. Principles of refrigeration at low temperatures.- B. Components of a liquefying system.- C. Representative helium liquefiers.- D. Liquid storage and transport vessels.- Electrical Conductivity of Metals and Alloys at Low Temperatures.- A. Historical summary and general concepts.- B. Notes on experimental methods and techniques.- C. Comparison of experimental data with theory.- D. Concluding remarks.- Thermal Conductivity of Solids at Low Temperatures.- I. Introduction.- II. Thermal conductivity of dielectric solids.- III. Thermal conductivity of metals and alloys: Electronic component.- IV. Thermal conductivity of metals and alloys: Lattice component.- V. Thermal conductivity of superconductors.- References.- Low Temperature Heat Capacity of Solids.- A. Theory.- I. Lattice modes.- II. Electronic modes.- B. Experimental techniques.- I. Calorimeter.- II. Measuring procedures.- C. Experimental results.- I. Lattice and electronic atomic heats of the elements.- II. Other sources of heat capacity.- a) Superconductivity.- b) Excitation modes.- c) Cooperative phenomena.- d) Size effect.- III. Miscellaneous measurements.- General References.- Sachverzeichnis (Deutsch-Englisch).- Subject Index (English-German).