Hassler Whitney was an American mathematician. He was one of the founders of singularity theory, and did foundational work in manifolds, embeddings, immersions, characteristic classes, and geometric integration theory. Hassler Whitney was born 23 March 1907 in New York City. Professor Whitney's specialty was geometry, particularly topology, including the study of multidimensional surfaces like spheres. He demonstrated, for example, that it is possible to plot a tour of the earth that visits each country once and only once - the Hamiltonian cycle. Professor Whitney received the National Medal of Science in 1976. He received bachelor's degrees in philosophy and in music at Yale and a doctorate in mathematics at Harvard. He taught mathematics at Harvard for a year and in 1931 was named to the National Research Council fellowship at Princeton.