James Peebles is the Albert Einstein Professor of Science (Emeritus) at Princeton University and is regarded as one of the greatest theoretical cosmologists of the last 50 years. His work has contributed enormously towards a better understanding of the Cosmic Microwave Background radiation, helping to consolidate the Big Bang as the prevalent theory to explain the origins of the universe. Peebles’ theories about Dark Energy and Dark Matter have been highly influential in explaining the structure of the universe, as have his statistical studies on the clustering and superclustering of galaxies. These contributions and many more earned him the Nobel Prize in Physics in 2019. In describing his work, the Nobel committee said, “Fundamental questions about the universe’s structure and history have always fascinated human beings. James Peebles’ theoretical framework, developed since the mid-1960s, is the basis of our contemporary ideas about the universe.” Peebles continues to do research on cosmology and has written extensively on the history of cosmology in the 20th century.