  An operator formalism for bosonization at finite temperature and density is
developed. We treat the general case of anyon statistics. The exact $n$-point
correlation functions, satisfying the Kubo-Martin-Schwinger condition, are
explicitly constructed. The invariance under both vector and chiral
transformations allows to introduce two chemical potentials. Investigating the
exact momentum distribution, we discover anyon condensation in certain range of
the statistical parameter. Another interesting feature is the occurrence of a
non-vanishing persistent current. As an application of the general formalism,
we solve the massless Thirring model at finite temperature, deriving the charge
density and the persistent current.
