Klára (Klari) Dán Von Neumann (18 August 1911 – 10 November 1963) was a scientist, and a pioneer computer programmer.
Klara was born in Budapest, Hungary on August 18, 1911 to Károly - Karl Dán and Camila Stadler. Her father had previously served in the Austro-Hungarian Army as an officer during World War I, and the family moved to Vienna to escape Bela Kun. Once the regime was overthrown, the family moved back. Her family was wealthy, and often held parties where Klara would meet many different people from various stations in life. At 14, Klara became a national champion in figure skating. She attended boarding school in England soon after. Klara was married four times. After her second divorce, she married John von Neumann in 1938. Klara married Carl Eckart in 1958. She reportedly took her own life in 1963.
Klara was one of the world's first computer programmers and coders. She helped solve mathematical problems using computer code. Klara wrote the code used on the MANIAC machine developed by John von Neumann and Julian Bigelow at the Los Alamos Scientific Laboratory. She was also involved in the design of new controls for ENIAC and was one of its primary programmers. She taught early weather scientists how to program. Klára wrote the preface to John von Neumann's posthumously published, influential Silliman Lectures, later edited and published by Yale University Press as "The Computer and the Brain". She features significantly in computing historian George Dyson's book, Turing's Cathedral: The Origins of the Digital Universe.