The nature and origins of renormalization group ideas in statistical p
hysics and condensed matter theory are recounted informally, emphasizi
ng those features of prime importance in these areas of science in con
tradistinction to quantum field theory, in particular: critical expone
nts and scaling, relevance, irrelevance and marginality, universality,
and Wilson's crucial concept of flows and fixed points in a large spa
ce of Hamiltonians.