Felix Hausdorff laid the foundations of set theoretic topology, which has evolved into an elaborate discipline that interacts with nearly every other field of mathematics. He precisely developed such basic notions as limits, continuous maps, connectedness, and compactness, which have become fundamental in building many kinds of mathematical structures. One of Hausdorff's revolutionary ideas, spaces of non-integer dimension,plays an important role in various topics, including geometric measure theory, the theory of dynamical systems, and in the description of the popularized notion of fractals. He was also a philosopher and author.

Hausdorff was born on November 8, 1868, in Breslau, Germany, which is now Wrocaw, Poland. His mother was Johanna Tietz Hausdorff; his father, Louis Hausdorff, was a dry goods merchant. The family moved to Leipzig, Germany, in 1871. The young Hausdorff eventually attended Leipzig University, where he studied astronomy and mathematics, earning his Ph.D. in 1891. His early research concentrated...