  Weyl metal is the first example of a conducting material with a nontrivial
electronic structure topology, making it distinct from an ordinary metal.
Unlike in insulators, the nontrivial topology is not related to invariants,
associated with completely filled bands, but with ones, associated with the
Fermi surface. The Fermi surface of a topological metal consists of
disconnected sheets, each enclosing a Weyl node, which is a point of contact
between two nondegenerate bands. Such a point contact acts as a source of Berry
curvature, or a magnetic monopole in momentum space. Its charge, or the flux of
the Berry curvature through the enclosing Fermi surface sheet, is a topological
invariant. We review the current state of this rapidly growing field, with a
focus on bulk transport phenomena in topological metals.
