Steven Weinberg is a Professor of Physics and Astronomy at the University of Texas, Austin. His research has covered a broad range of topics in quantum field theory, elementary particle physics, and cosmology, and he has been honored with numerous awards, including the Nobel Prize in Physics, the National Medal of Science, and the Heinemann Prize in Mathematical Physics. The American Philosophical Society awarded him the Benjamin Franklin medal, with a citation that said he is 'considered by many to be the preeminent theoretical physicist alive in the world today'. He is a member of several academies in the USA and abroad, including the US National Academy of Sciences and Britain's Royal Society. He has written several highly regarded books, including Gravitation and Cosmology (1972), a three-volume work The Quantum Theory of Fields (Cambridge, 2005), Cosmology (2008), and Lectures on Quantum Mechanics (Cambridge, 2nd edition, 2015).