I review basic concepts and recent developments in the field of optical properties of few and many Fröhlich polarons in systems of different dimensionality. The key subjects are: comparison of the optical conductivity spectra for a Fröhlich polaron calculated within the all-coupling path-integral based theory [1] with the results obtained using the numerical Diagrammatic Quantum Monte Carlo (DQMC) method [2] and the recently developed analytical approximations [3]; the scaling relations for Fröhlich polarons in different dimensions; the many-body problem (including the electron-electron interaction and Fermi statistics) in the few- and manypolaron theory [4]; the theory of the optical absorption spectra of many-polaron systems [5]; the ground-state properties and the optical response of interacting polarons in quantum dots [6]. In the weak coupling regime, both the extended memory-function formalism (MFF) with phonon broadening [3] and DSG [1] are in very good agreement with the DQMC data [2], showing significant improvement with respect to the weak coupling perturbation approach. The weak coupling limit gained some improvements by including 2-phonon processes. For 4 ≤ α ≤ 8, where DSG underestimates the peak width, the damping, introduced in the extended MFF approach, becomes crucial. Comparing the peak and shoulder energies, obtained by DQMC, with the peak energies, given by MFF, and the Franck-Condon (FC) transition energies from the strong-coupling expansion [3], it is concluded that as α increases from 6 to 10 the spectral weights rapidly switch from the dynamic regime, where the lattice follows the electron motion, to the adiabatic regime dominated by FC transitions. In the intermediate electron-phonon coupling coupling regime, 6 < α < 10, both adiabatic FC and nonadiabatic dynamical excitations coexist. The accurate numerical results obtained from DQMC – modulo the linewidths for α > 6 – and from the recent analytical approximations [3] confirm the essence of the mechanism for the optical absorption of Fröhlich polarons, proposed in [1].