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Willem J. Kolff (1911–2009) was a Dutch-born physician and biomedical pioneer who invented the first practical artificial kidney and helped develop artificial organs, including early artificial heart technology, saving countless patients suffering from kidney and heart failure.

Hans Koning (1921–2007), born Hans Koningsberger, was a Dutch-born American novelist, journalist, and screenwriter. A former member of the Dutch resistance during World War II, he later wrote widely for major magazines and newspapers.

Willem de Kooning (1904–1997) was a Dutch-born American painter and leading figure in Abstract Expressionism. Known for powerful, expressive works such as his Woman series, he became one of the most influential artists of the twentieth century.

Tjalling C. Koopmans (1910–1985) was a Dutch-born American economist who won the 1975 Nobel Prize in Economics for work on optimal resource allocation and linear programming, helping establish the field of mathematical economics.