David Harker (October 19, 1906 – February 27, 1991) was an American medical researcher who according to The New York Times was "a pioneer in the use of X-rays to decipher the structure of critical substances in the life process of cells".
[1][2] He is also well known for Harker–Kasper inequalities (statistical relationships between the phases of structure factors), which he devised in collaboration with John S.
Harker was a member of the National Academy of Sciences,[2] director of the protein structure program at the Polytechnic Institute of Brooklyn,[1] director of the Center for Crystallographic Research at Roswell Park Comprehensive Cancer Center,[1][5] and the head of the crystallography division of General Electric.
His research interests while at HWI turned towards mathematical aspects of crystallography, including magnetic space groups and infinite polyhedra.
[2] Harker was awarded the Gregori Aminoff Prize from the Swedish Academy in 1984.