Henry Gwyn Jeffreys Moseley's great contribution to science was his ordering of the elements by examining their X-ray spectra, thus creating the periodic table. His work, which ranks among the most profound discoveries of the twentieth century, was cut short when the scientist was killed during World War I. Although he never received a major award for his research, Moseley's accomplishments laid the groundwork for a number of later scientific developments.

Henry Gwyn Jeffreys Moseley (widely known as "Harry") was born on November 23, 1887, at Weymouth, England. He was the only son of Henry Nottidge Moseley, a professor of human and comparative anatomy at the University of Oxford. He had also served as a naturalist on the famous voyages of the Challenger in that vessel's studies of the world's oceans. Both sides of the family included a number of eminent scientists, including a paternal grandfather who was the first...