The "Brownian movement" was first described in 1828 by the botanist Robert Brown. While investigating the pollen of several different plants, he observed that pollen dispersed in water in a great number of small particles which he perceived to be in uninterrupted and irregular "swarming" motion. For more than half a century following, a score of scientists studied this motion, common to organic and inorganic particles of microscopic size when suspended in a liquid, to determine the causes and the dynamics of the motion.This volume contains five papers investigating the dynamics of this phenomenon by Albert Einstein. Written between 1905 and 1908, the papers evolve an elementary theory of the Brownian motion, of interest not only to mathematicians but also to chemists and physical chemists. The titles of the papers are: "Movement of Small Particles Suspended in a Stationary Liquid Demanded by the Molecular-Kinetic Theory of Heat"; "On the Theory of the Brownian Movement"; "A New Determination of Molecular Dimensions"; "Theoretical Observations on the Brownian Motion"; and "Elementary Theory of the Brownian Motion." The editor, R. Fürth, has provided notes at the end of the book which discuss the history of the investigation of the Brownian movement, provide simple elucidations of the text, and analyze the significance of these papers.