Nobel Prize in Physics Recipient. Dr. Manne Siegbahn, a Swedish scientist, received the 1924 Nobel Prize in Physics "for his discoveries and research in the field of X-ray spectroscopy". He was the father of Nobel Prize in Physics 1981 recipient Kai Siegbahn. The case of a parent and child both being Nobel Prize recipients is not that rare. Besides Marie Currie and her daughter, there have been a total of four father and son recipients. His education started in the University of Lund in 1906, where he received his doctorate degree in 1911. From 1907 to 1911 at the Physics Institute of the University, he was an assistant to Professor Johannes R. Rydberg, the noted scientist of the Rydberg Formula, which describes the wavelengths of photons emitted by changes in the energy level of an electron in a hydrogen atom. He went on to succeed Rydberg in this position after Rydberg's death in December of 1919. Their close relationship led Rydberg's biography being written by Siegbahm. In 1923 Seigbahn became Professor of Physics at the University of Uppsala, and in 1937 was appointed as Research Professor of Experimental Physics, at the Royal Swedish Academy of Sciences. He became the first Director of the Physics Department of the Nobel Institute of Academy the same year. His early experiments were concern with problems of electricity and magnetism. After 1912, his research was devoted to X-ray spectroscopy, developing new methods of use. He summarized his work in his 1923 book, "Spectroscopy of X-Ray," which was published in English in 1924 and became a scientific classic text. Eventually, the main focus of his experiments was nuclear science. He traveled to many countries in Europe along with the United States and Canada visiting all the scientific institutes. On the invitation of the Rockefeller Foundation, he gave lectures at several universities including Columbia, Yale, Harvard, Cornell, Chicago, Berkeley, and Montreal. He received numerous honors besides the Nobel Prize such as awards from England: Hughes Medal in 1934, the Rumford Medal from the Royal Society in 1940 and the Duddel Medal from the Physical Society in 1948. He received numerous honorary doctorate degrees and was a member of the Royal Society, London and Edinburgh, of the Academie des Sciences, Paris, and of several other academies. Besides his son, Kai, he was the father of an older son, Bo, who served as Swedish Ambassador to Morocco, Israel, and other countries.