Guido Walz is professor for applied mathematics at the Wilhelm-Büchner-Hochschule, Darmstadt, and lecturer at the Baden-Württemberg Cooperative State University in Mannheim. He is editor oft he six-volume Lexikon der Mathematik and author of numerous publications and textbooks, including Mathematik für Hochschule und Duales Studium.Thomas Rießinger studied mathematics at the University of Mannheim and received his doctorate there in 1987. After working as a research assistant and systems analyst, he became a professor of mathematics and computer science at the University of Applied Sciences in Frankfurt am Main in 1992. He is the author of several textbooks about mathematics.Frank Zeilfelder received his PhD (mathematics) in 1996 and his habilitation in 2002. In addition to various research stays abroad, he worked at the MPI for Computer Science in Saarbrücken, the University of Duisburg-Essen and the TU Darmstadt. Currently, he holds a position as "Fachberater Mathematik" at the RP Karlsruhe and works as a teacher for mathematics and computer science at the Carl-Benz-Schule in Mannheim.