Over the last 10 years, research in the terahertz (THz) frequency region of the electromagnetic spectrum has grown dramatically. The most significant development has been the demonstration of the first THz frequency quantum cascade laser (QCL) in 2002 by my EC FP-V consortium, WANTED. These advances have been accompanied by an equally important industrial applications-pull, with exploitation envisaged in the pharmaceutical and security sectors, for medical imaging and atmospheric sensing, and for high frequency electronics and communications. Yet, the enormous potential of the THz range has still to be unlocked, principally as there remains a lack of versatile, compact THz systems. My vision here is to address this, creating a step-change in the exploitation of THz technology. I will develop the patterning of periodic and aperiodic grating structures both lithographically, and for the first time, electronically, to engineer the photonic properties of THz QCLs. I will demonstrate the use of surface acoustic waves to modulate QCLs piezoelectrically, creating dynamically tunable sources. A continuous wave system-on-a-chip based on a QCL source, waveguide and integrated solid state detectors will be developed, together with an on-chip continuous-wave THz interferometer, and proven in the study of low-dimensional, nanostructured systems. I will develop a compact fibre-coupled broadband THz system, based on 1.55µm fs-laser excitation of photoconductive antennae. Investigations into the fundamental science underlying THz QCLs will include magnetic field gain measurements of THz QCLs to probe the role of non-Markovian transport in superlattice optoelectronic structures. This programme, comprising the symbiotic development of THz engineering and science, will be unique internationally and will open new opportunities and directions in the study and exploitation of THz frequency electronics and photonics.