  We investigate N-point string scattering amplitudes in AdS_3 space. Based on
recent observations on the solutions of KZ and BPZ-type differential equations,
we discuss how to describe the string theory in AdS_3 as a marginal deformation
of a (flat) linear dilaton background. This representation resembles the called
"discrete light-cone Liouville" realization as well as the FZZ dual description
in terms of the sine-Liouville field theory. Consequently, the connection and
differences between those and this realization are discussed. The free field
representation presented here permits to understand the relation between
correlators in both Liouville and WZNW theories in a very simple way. Within
this framework, we discuss the spectrum and interactions of strings in
Lorentzian AdS_3.
