Spark Plasma Sintering (SPS) or field activated sintering technique (FAST) is an unconventional and novel powder consolidation process via simultaneous application of special pulsed current and mechanical pressure. SPS or FAST has demonstrated its benefits as a rapid processing avenue, with application to the largest variety of materials - ceramics, metals, polymers, semiconductors - and which results in enhanced final properties. This work covers the physical phenomena, multi-scale analytical and numerical models, experimental studies, and application of FAST processing. Specifically, a coupled thermal-electric-densification framework for the design and optimization of FAST type processing has been proposed and implemented into a finite element package. A discrete finite element method is also developed to determine the effective thermal conductivity in a particulate system with realistic microstructure. Finally, FAST simulation of a hip joint replacement has been conducted.