  The main notions of semiclassical scalar electrodynamics in different gauges
(Hamiltonian, Couloumb, Lorentz) are discussed. These are semiclassical states,
Poincare transformations, fields, observables, gauge equivalence. General
properties of these objects are formulated as axioms of semiclassical theory;
they are heuristically justified. In particular, a semiclassical state may be
viewed as a set of classical background field and quantum state in the external
background. Superpositions of these "elementary" states can be also considered.
Set of all "elementary" semiclassical states forms a semiclassical bundle, with
base being classical space and fibres being quantum states in the external
background. Quantum symetry transformations (Poincare and gauge
transformations) are viewed semiclassically as automorphisms of the
semiclassical bundle. Specific features of electrodynamics are investigated for
different gauges.
