This book mainly seeks to explain, define and update the recurring forms of populism in the 21st century. Examples used in this Introduction are limited to English speaking countries. But populism's existent expressions are ecumenically global. Like any long-lasting perennial organism it is sturdy and comes in a variety of forms adaptable to environmental changes.  In political or cultural terms its expression has been neither exclusively left, center, nor right. Populism contains multitudes, dates back centuries before it was identified with its modern name.Populism has become a hot button issue in the recent times. The UK's Sunday heavyThe Guardianpublished about 300 articles in 1998 that used the term "populism" or "populist" and by 2016 its use had skyrocketed to over 2,000. And growing. Probably the single greatest catalyst to date that injected populism into the world's Internet common discourse, that infused it into journalism right, left and centerand awakened populist political activism was the Great Recession of 2007-08 and the subsequent global deprivations it engendered. In today's world populism promises to remain and renew its intensity due to the covid-19 pandemic's deleterious effects on most nations middle and low-income groups, specially minorities. These are some reasons among many why it is time for populism to be relocated, identified and given refreshed 21st understandings. It has a shifting nature among people, events, causes that constantly demands fresh studies. It is a social and cultural phenomenon both universal and particular.  In our 21st century world it is a product of our shared cultures and each our own exceptional deep culture.This Encyclopedia is unique in its composition as it includes all the major disciplines of Social Sciences and thus will be a one stop source of nine different disciplines looking at new populism.