Abstract:20.1 Introduction20.2 Terahertz time-domain spectroscopy (THz-TDS) spectroscopy set-up and analysis20.3 Terahertz time-domain spectroscopy (THz-TDS): identification, quantification and analysis20.4 Terahertz time-domain imaging (THz-TDI): imaging set-up and analysis20.5 Terahertz time-domain imaging (THz-TDI): process monitoring, spectroscopic imaging and chemical mapping20.6 Conclusions and future trends20.7 Acknowledgement