After explaining what modernism is by contrast, this book explains the development of postmodernism from its beginnings in the ideas of Friedrich Nietzsche through its development by the French postmodernists and Pop Art to by the 1970s becoming a widespread ideology since then ever more pervading our Western educational, artistic, political, mass media, and religious institutions as well as the worldviews and values of people on a mass scale. It explains how this ideology has severely degraded these institutions, worldviews, and values also on a grand scale, mainly by its extreme and crude materialism and relativism and by undermining values of progress, truth, morality or goodness, and aesthetic beauty. I trace the beginnings of postmodernism to Nietzsche, who proposed that the old verities of philosophical ethics should be discarded in favor of his terms of master and slave forms of morality. I charge that by relativizing ethics, Nietzsche opened a cultural road towards ever more relativism in philosophy, a relativism that eventually led to academic postmodernism, then came to pervade our society on a mass scale, and that this turn toward relativism has been retrograde in terms of social progress. Though Nietzsche had contempt for the so called “last man” of a corrupted society -- people who have lost any sense of great ideals to live for but instead mainly live for creature comforts, I show how his relativism opened a path towards such a last man now becoming a common social type. A chapter focused on art discusses "Romantic modernist" art and its major manifestations during the nineteenth and twentieth centuries, all of which resisted the rationalization and disenchantment of modern life and the ethos of instrumental reason. I then trace the gradual dissolution of Romantic modernism, beginning with the early twentieth century Dadaist movement and culminating with the forms of neo-Dadaism that are celebrated by the art world today. A chapter discusses how postmodernist relativism and nihilism are manifest in many of the new age and alternative religions now, tending to lead their followers towards more social and political complacency. Though these spiritual subcultures tend to see themselves as socially nonconforming, I show how they actually often tend to reflect a conforming postmodernist worldview. I show how postmodernist ideology, under a false guise of social criticism, actually tends to serve the interests of oppressive power structures and oppressive social status quos. I show how present identity politics fashions, while represented as "progressive," actually serve a globalist agenda to concentrate ever more wealth and power to international elites. A chapter on propaganda explains the dynamics of current postmodernist propaganda institutions and how one can seek to overcome their influences. My chapter on the corruption of academia might be read in part as a participant-observer study, much as a researcher goes undercover to study a subculture then reports on the findings. As I show, I found many problems in academia to report. Chapter Seven discusses how the degrading effects of postmodernism are now often manifest in the institution of marriage. I discuss current MGTOW or Men Going Their Own Way ideas as reactions to this and discuss how Simone de Beauvoir’s second-wave feminist ideas might now also be applied to understanding current typical sex roles of men. The book concludes by exploring how people can prevent themselves from being degraded by the postmodernist ideology by infusing truth, ethics, beauty, idealism, and enchantment into their lives. My critiques don't neatly fit conventional "left" and "right" templates. I find problems with both. This manuscript has been expanded far beyond its original 2018 version, is carefully re-edited, and in its conclusion, has added analysis of the events of 2020. About me, see the bio area below.