Bosonization of degenerate fermions yields insight both into Landau-Fermi l
iquids, and into non-Fermi liquids. We begin our review with a pedagogical
introduction to bosonization, emphasizing its applicability in spatial dime
nsions greater than one. After a brief historical overview, we present the
essentials of the method. Well known results of Landau theory are recovered
, demonstrating that this new tool of many-body theory is robust. Limits of
multidimensional bosonization are tested by considering several examples o
f non-Fermi liquids, in particular the composite fermion theory of the half
-filled Landau level. Nested Fermi surfaces present a different challenge,
and these may be relevant in the cuprate superconductors. We conclude by di
scussing the future of multidimensional bosonization.