We present a combined theoretical and experimental investigation of the generation of few-cycle terahertz (THz) pulses via the nonlinear effect of optical rectification and of their coherent detection via electro-optic sampling. The effects of dispersive velocity matching, absorption of the optical and the THz waves, crystal thickness, pulse diameter, pump pulse duration, and two-photon absorption are discussed. The theoretical calculations are compared with the measured spectra of THz pulses that have been generated and detected in crystals of the highly nonlinear organic salt 4- $N,N$ -dimethylamino- $4^{\prime }$ - $N^{\prime }$ -methyl stilbazolium tosylate (DAST). The results are found to be in agreement with the theory. By the selection of the optical pump wavelength between 700 and $1600\mathrm{nm}$ , we achieved several maxima of the overall generation and detection efficiency in the spectral range between 0.4 and $6.7\mathrm{THz}$ , with an optimum at $2\mathrm{THz}$ generated with $1500\mathrm{nm}$ laser pulses.