The review is devoted to theoretical investigations of propagation of elect
romagnetic and acoustic waves in layered conductors of organic origin. Atte
ntion is focussed on spectroscopic possibilities for studying the electron
structure of organic quasi-two-dimensional conductors, which is of great im
portance for understanding physical processes in these materials. High-freq
uency and magnetoacoustic effects considered in this review are typical of
quasi-two-dimensional conductors and quite informative. The analysis of the
se effects makes it possible to study in detail the electron energy spectru
m and relaxation properties of charge carriers in layered conductors. (C) 1
999 American Institute of Physics. [S1063-777X(99)00111-5].