"in 1913, English physicist Henry Moseley created an elegant method for organizing the elements of the periodic chart. His chart is organised based on atomic number instead of atomic weight. Soon enough, scientists discovered that there were seven missing elements between Hydrogen (element no. 1) and Uranium (element no. 92).
In this book, Eric Scerri offers interesting stories about those seven elements: Protactinium, Hafnium, Rhenium, Technetium, Francium, Astatine and Promethium. The book follows the historical sequence of the discovery, approximately between WWI and WWII. It starts with the isolation of Protactinium in 1917, concluding with the isolation of Promethium in 1945. The book also follows the research that preceded the discovery of each element. It discusses pivotal experiments, concerned chemists, the chemical nature of new elements, and their applications in science and technology."