Steven Weinberg, a theoretical physicist who discovered that two of the universe’s forces are really the same, for which he was awarded the Nobel Prize, and who helped lay the foundation for the development of the Standard Model, a theory that classifies all known elementary particles in the universe, making it one of the most important breakthroughs in physics in the 20th century, died August 30 in a hospital in Austin, TX. He was 88.

Although he had the respect, almost awe, of his colleagues for his scientific abilities and insights, he also possessed a rare ability among scientists to communicate and explain abstruse scientific ideas to the public. He was a sought-after speaker, and he wrote several popular books about science, notably The First Three Minutes: A Modern View of the Origin of the Universe (1977).

He wrote many other books, including on the history of science, To Explain the World: The Discovery of Modern Science (2015), and three volumes totaling 1,500 pages on quantum field theory, which merges classical physics, special relativity, and quantum mechanics. The series is widely regarded as the definitive text on the subject.