This work aims to unravel what controls short-range order stabilities and characteristics, understand fundamentals of short-range order-assisted deformation micro/nano-mechanics, and design novel complex concentrated alloys that overcome current strength and toughness limits. It is necessary to understand how specific aspects of short-range order chemistry, size, and strength can be controlled, and how such variations would influence the interaction with dislocations. To this end, one of the most important challenges is regarding characterization. The typical size of the short-range ordered zones reaches the resolution limits of the conventional microscopy and diffraction tools such as the transmission electron microscopy, the atom probe tomography, and the x-ray diffraction. The research team will employ a novel, multi-pronged approach, combining theoretical modeling (ab-initio density functional theory calculation, Monte-Carlo simulation, and molecular dynamics), metallurgical processing (fabrication & testing), and atomically-resolved advanced structural characterization techniques (resonant x-ray scattering, in-situ scanning electron microscopy, and revolving scanning transmission electron microscopy) in order to overcome this challenge, and to link atomic-scale short-range order-characteristics to engineering properties at the macro-scale.