Dr. Muller began his career as a graduate student under nobel laureate Luis Alvarez doing particle physics experiments and working with bubble chambers. During his early years he also helped to cocreate accelerator mass spectroscopy and made some of the first measurements of anisotropy in the cosmic microwave background.
Subsequently, Dr. Muller branched out into other areas of science, and in particular the earth sciences. His work has included attempting to understand the ice ages, dynamics at the core-mantle boundary, patterns of extinction and biodiversity through time, and the processes associated with impact cratering. One of his most well known proposals is the Nemesis hypothesis suggesting that the sun could have an as yet undetected companion star, whose perturbations of the Oort cloud and subsequent effects on the flux of comets entering the inner solar system could explain an apparent 26 million year periodicity in extinction events.
Richard Muller was named a MacArthur Foundation Fellow in 1982. He also received the Alan T. Waterman Award from the National Science Foundation "for highly original and innovative research which has led to important discoveries and inventions in diverse areas of physics, including astrophysics, radioisotope dating, and optics." More recently, he received a distinguished teaching award from UC Berkeley . His "Physics for Future Presidents" series of lectures, in which Muller teaches a synopsis of modern qualitative (i.e. without resorting to complicated math) physics, has been released publicly on YouTube by UC Berkeley.
On Thurday Dec 3rd 2009 Richard Muller announced his retirement in his Letters in Science C70V lecture Dec 3rd 2009 Lecture 14m 15sec into the lecture. He will continue to guest lecture the course which he created and has the popular name "Physics for Future Presidents" but Bob Jacobsen will be taking over the course. Richard Muller said he will be putting most of his time into "energy, environment, global warming, alternative energy" 14m 55s into the same lecture.
For several years, he was a monthly columnist with MIT's Technology Review. In his August 2003 column on the polygraph machine used in lie detection examinations, Muller asserted that "the polygraph procedure has an accuracy between 80 and 95 percent." In contrast, the National Academy of Sciences found that there is "little basis for the expectation that a polygraph test could have extremely high accuracy."
Muller is President and Chief Scientist of Muller & Associates, an international consulting group specializing in energy-related issues. 
Muller is married to architect Rosemary Muller.
Richard A. Muller (born January 6, 1944) is a physicist who works at the University of California and Lawrence Berkeley National Laboratory. In his "Physics for Future Presidents" series of lectures, he teaches a synopsis of modern qualitative physics, without resorting to complicated math.