  Classical model of light in helicity formalism is presented. Then quantum
point of view at photons -- construction and interpretation of photon wave
function is proposed. Quantum mechanics of photon is investigated. The Bia\l
ynicki -- Birula scalar product $\langle {\bf \Psi}_{1}|{\bf
\Psi}_{2}\rangle_{BB}$ and the generalized Hermitian conjugation
$\widehat{\gamma}^{+\hspace{-0.45em}+}$ of linear operator $\widehat{\gamma}$
are discussed. Quantum description of light on a phase space is developed. A
photon Wigner function is built.
