Jürgen Kurt Moser (July 4, 1928 – December 17, 1999) was a German-American mathematician, honored for work spanning over four decades, including Hamiltonian dynamical systems and partial differential equations. Life Moser's mother Ilse Strehlke was a niece of the violinist and composer Louis Spohr. His father was the neurologist Kurt E. Moser (July 21, 1895 – June 25, 1982), who was born to the merchant Max Maync (1870–1911) and Clara Moser (1860–1934). The latter descended from 17th century French Huguenot immigrants to Prussia. Jürgen Moser's parents lived in Königsberg, German empire and resettled in Stralsund, East Germany as a result of the second world war. Moser attended the Wilhelmsgymnasium (Königsberg) in his hometown, a high school specializing in mathematics and natural sciences education, from which David Hilbert had graduated in 1880. His older brother Friedrich Robert Ernst (Friedel) Moser (August 31, 1925 – January 14, 1945) served in the German Army and died in Schloßberg during the East Prussian offensive. Moser married the biologist Dr. Gertrude C. Courant (Richard Courant's daughter, Carl Runge's granddaughter and great-granddaughter of Emil DuBois-Reymond) on September 10, 1955 and took up permanent residence in New Rochelle, New York in 1960, commuting to work in New York City. In 1980 he moved to Switzerland, where he lived in Schwerzenbach near Zürich. He was a member of the Akademisches Orchester Zürich. He was survived by his younger brother, the photographic printer and processor Klaus T. Moser-Maync from Northport, New York, his wife, Gertrude Moser from Seattle, their daughters, the theater designer Nina Moser from Seattle and the mathematician Lucy I. Moser-Jauslin from Dijon, and his stepson, the lawyer Richard D. Emery from New York City. Moser played the piano and the cello, performing chamber music since his childhood in the tradition of a musical family, where his father played the violin and his mother the piano. He was a lifelong amateur astronomer and took up paragliding in 1988 during a visit at IMPA in Rio de Janeiro. Work Moser completed his undergraduate education at and received his Dr. rer. nat. from the University of Göttingen in 1952, studying under Franz Rellich. After his thesis, he came under the influence of Carl Ludwig Siegel, with whom he coauthored the second and considerably expanded English language edition of a monography on celestial mechanics. Having spent the year 1953 at the Courant Institute of New York University as a Fulbright