  This paper is a brief survey of the Balitskii-Fadin-Kuraev-Lipatov (BFKL)
approach for the description of hard or semi-hard processes in the so-called
Regge limit of perturbative QCD. The starting point is a fundamental property
of perturbative QCD, the gluon Reggeization. This property, combined with
s-channel unitarity, allows to predict the growth in energy of the amplitude of
hard or semi-hard processes with exchange of vacuum quantum numbers in the
$t$-channel. When also the so-called impact factors of the colliding particles
are known, then not only the behavior with the energy, but the complete
amplitude can be determined. This was recently done, for the first time with
next-to-leading order accuracy and for a process with colorless external
particles, in the case of the electroproduction of two light vector mesons.
