  We review the basic idea behind resource theories, where we quantify quantum
resources by specifying a restricted class of operations. This divides the
state space into various sets, including states which are free (because they
can be created under the class of operations), and those which are a resource
(because they cannot be). One can quantify the worth of the resource by the
relative entropy distance to the set of free states, and under certain
conditions, this is a unique measure which quantifies the rate of state to
state transitions. The framework includes entanglement, asymmetry and purity
theory. It also includes thermodynamics, which is a hybrid resource theory
combining purity theory and asymmetry. Another hybrid resource theory which
merges purity theory and entanglement can be used to study quantumness of
correlations and discord, and we present quantumness in this more general
framework of resource theories.
