Notes:
This is the story we tell Philistines who ask, “Why on earth do you want to study muons? What are they good for?” As it happens, they are excellent magnetic probes in solids and unprecedented as a light isotope of hydrogen; but the real reason we (or I, at least) study muons in matter is an obsessive fascination with the idea of being able to “see” what they do!
I believe this obsession has helped me look past the standard themes and notice the things muons do (as they slow down and stop in matter) that grown-in hydrogen or other magnetic resonance probes do not.