Carl Ludwig Siegel is considered to be one of the greatest mathematicians of the 20th century. Nothing is known about his life prior to his admission at the Humboldt University at the age of nineteen. Although he initially wanted to pursue astronomy, his interest was turned towards number theory under the guidance of his teachers at Humboldt. Later, he wrote his dissertation on Diophantine approximations, earning his doctoral degree from the University of Göttingen, beginning his career at Johann Wolfgang Goethe-Universität of Frankfurt am Main two years later. But even before that, he was able to establish himself as an eminent mathematician with his ‘Thue–Siegel–Roth theorem’. An anti-Nazi and an antimilitarist, he left his homeland at the onset of the Second World War, teaching in the USA from 1940 to 1951. Otherwise, he lived mostly in Germany devoting himself to teaching and mathematical research. Today, he is especially noted for his work on number theory and celestial mechanics. Apart from publishing number of groundbreaking papers on these subjects, he had also written several textbooks on them.
