"Boltzmann’s Lectures on Gas Theory is an acknowledged masterpiece of theoretical physics... still... [of] considerable scientific value today. It contains a comprehensive exposition of the kinetic theory of gases by a scientist who devoted a large pail of his own career to it, and brought it very nearly to completion as a fundamental part of modern physics. ...Ludwig Boltzmann ...played a leading role in the nineteenth-century movement toward reducing the phenomena of heat, light, electricity, and magnetism to "matter and motion"—in other words, to atomic models based on Newtonian mechanics. His own greatest contribution was to show how... mechanics... previously ...regarded as deterministic and reversible in time, could be used to describe irreversible phenomena in the real world on a statistical basis. His original papers on the statistical interpretation of thermodynamics, the H-theorem, transport theory, , the of gases... occupy about 2,000 pages... [N]ot even the handful of experts on kinetic theory could claim to have read everything he wrote. ...Boltzmann decided to publish his lectures, in which the most important parts of the theory, including his ...contributions, were carefully explained. ...[H]e included his mature reflections and speculations on such questions as the nature of irreversibility and the justification for using statistical methods in physics. His Vorlesungen über Gastheorie was... the standard reference... for advanced researchers, ...[and] a popular textbook ...for the first quarter of the [20th] century ..."