  The paper concerns the effective field theory methods used to study the low
energy structure of systems with a spontaneously broken symmetry. I first
explain how the method works in the context of quantum chromodynamics and then
discuss a few general aspects, related to the universality of effective
theories. In particular, I compare some of the effective field theories used in
condensed matter physics with those relevant for particle physics. (Talk given
at the Bose Conference, Jan.94, Calcutta, BUTP 94/17)
