  We introduce a class of states, called minimally entangled typical thermal
states (METTS), designed to resemble a typical state of a quantum system at
finite temperature with a bias towards classical (minimally entangled)
properties. These states reveal in an intuitive way properties such as
short-range order which may be hidden in correlation functions. An algorithm is
presented which, when used with the density matrix renormalization group
(DMRG), is faster by a factor of $10^3 - 10^{10}$ than previous heat-bath
approaches for thermally averaged quantities.
