  Features of electronic currents in solids are truly diverse depending on
circumstances, e.g. non-equilibrium transport currents leading to dissipation
and persistent currents flowing in equilibrium. Differences between these
currents may be clear in many cases, while there are some where they are not.
Results of theoretical studies on the latter cases will be introduced briefly
focusing on the inter-band effects of magnetic fields in orbital magnetisms and
Hall effects of Dirac electrons.
