The far IR or THz spectral region, which lies below 400 cm-1, is important for the study of inorganic substances which involve vibrations of heavier atoms. External or lattice vibrations, which are sensitive to crystal structure and polymorphism, can be seen also for both inorganic and organic solid samples. However it was not always that straightforward to obtain high quality far IR spectra, due to inherent weak sources and rather insensitive room temperature detectors, but the latest technical developments now make it much easier. In particular, the VERTEX 70(v) FT-IR spectrometers offer a wide band mid to far IR beamsplitter and detector combination to access the complete spectral range in one go (VERTEX FM option). There is an automatic beamsplitter changer for the VERTEX 80v vacuum spectrometer which enables unattended multi range spectroscopy without breaking the spectrometer vacuum which would otherwise disturb the measurement.