 For more than 5,000 years, metals and alloys have been formed in roughly the same way, propelling civilization from the Bronze Age to the Industrial Revolution and to the Aerospace Age. Now, there's a new technique on the horizon that could help us take another big leap forward. It's called high entropy alloying, and the latest focus issue of the Journal of Materials Research showcases scientists and engineers' latest efforts in understanding high entropy alloys and their potential applications. Traditional physical metallurgy uses an element with attractive properties as a base and adds small amounts of other elements to improve those and other properties. Over thousands of years, various elements have been used as the base, first copper, then iron, then one by one across the periodic table, until researchers developed the first titanium alloys in the 1950s. It's a method that's proven incredibly effective. But there are signs that the approach may be reaching its natural limit. In fact, there are no new stable metallic elements to give new elemental alloy bases. That limitation has fueled research into high entropy alloys. Rather than basing alloys on a single element, high entropy alloys use concentrated blends of five or more principal elements to form an alloy base. Conceptually, this technique represents a shift in focus from the boundaries of a multi-component phase diagram to the center, a vast and underexplored space in materials science and engineering. This focus issue of the Journal of Materials Research guides the reader through the latest advancements across this frontier. From fundamental studies on the formation, thermodynamics, processing and mechanical and environmental properties of high entropy alloys to research examining their use in energy and defense applications due to their high strength, superconductivity and resistance to fatigue, fracture, corrosion and irradiation. For a wide-ranging look at the latest developments in the fast-developing field, click on the link below to access the journal webpage.