Robert Walker passed away

Robert Walker, the coauthor of the celebrated textbook "Mathematical
Methods of Physics" (by Jon Mathews and Robert Walker) and retired
professor of Physics at Caltech died on January 4th in New Mexico. He
was 85.

Walker's specialization was in experimental high energy physics. He was
a popular teacher and his research spanning 30 years at Caltech
synchrotron was also useful in his longtime colleague Richard Feynman's
theoretical studies of elementary particles.

After retiring from Caltech in 1981, Walker spent his time building
harpsichords at his home in Santa Fe.