Physicist. He is best remembered for his development of statistical mechanics to explain and predict how the properties of atoms determine the visible properties of matter. Born Ludwig Eduard Boltzmann his father was a government revenue official. He received his primary education at home from a private tutor and attended high school in Linz, Austria. In 1863 he studied physics at the University of Vienna, receiving his PhD degree in 1866, with his dissertation being on the kinetic theory of gases. In 1867 he became a lecturer and worked as an assistant to one of his professors, Joseph Stefan, for another two years. In 1869, with the help of a letter of recommendation from Stefan he was appointed a full Professor of Mathematical Physics at the University of Graz, in Graz, Austria. The same year he spent several months in Heidelberg, Germany working with Robert Bunsen and Leo Konisberger and in 1871 he was in Berlin, Germany, working with Gustav Kirchoff and Hermann von Helmholtz. In 1873 he joined the University of Vienna as Professor of Mathematics and remained there until 1876. He then went back to Graz to become the Chair of Experimental Physics and remained there for the next fourteen years and developed his statistical concept of nature. In 1885 he became a member of the Imperial Austrian Academy of Sciences and in 1887 he became President of the University of Graz followed by becoming an elected member of the Royal Swedish Academy of Sciences in 1888. In 1890 he was appointed to the Chair of Theoretical Physics at the University of Munich in Bavaria, Germany; three years later he succeeded Stefan as professor of Theoretical Physics at the University of Vienna. Boltzmann spent a great deal of effort in his final years defending his theories. He did not get along with some of his colleagues in Vienna, particularly Ernst Mach, who became a professor of philosophy and history of sciences in 1895. That same year Georg Helm and Wilhelm Ostwald presented their position on Energetics, at a meeting in Lübeck in 1895, in which they saw energy, and not matter, as the chief component of the universe. However, Boltzmann's position carried the day among other physicists who supported his atomic theories in the debate. In 1900 he went to the University of Leipzig, Germany on the invitation of Wilhelm Ostwald and in 1902, after the retirement of Mach due to bad health, he came back to the University of Vienna and founding the Austrian Mathematical Society together with Gustav von Escherich and Emil Müller in 1903. In Vienna, he not only taught physics but also lectured on philosophy. His lectures on natural philosophy were very popular, and received a considerable amount of attention at that time. His first lecture was an enormous success. Because of the great successes of his philosophical lectures, the Emperor invited him for a reception at his Palace. He was subject to rapid alternation of depressed moods with elevated, expansive or irritable moods, likely the symptoms of undiagnosed bipolar disorder, and had attempted suicide on several occasions. While on summer vacation in Duino, in the province of Trieste, Italy, he hanged himself during an attack of depression at the age of 62. Soon after his death his theories were proven to be correct.