The English word “eschatology” is a fairly late theological term, apparently not put into common use before the nineteenth century. Its first use, however, appears as far back as in Germany in 1644 in the last section of Philip Heinrich Friedlieb’s Dogmatics. That section was titled: Eschatologia seu Florilegium theolgicum exhibens locorum de moret, resurrectione martuoru, extreme iudicio, cosummatione seculi, inferno sue maorte aeterna et denique vita eterna (which explains why you never see it mentioned on a bumper sticker).
The term “Eschatology” is the compound of two Greek terms: eschatos, which means “last,” and logia, which means “word, discourse.” Etymologically then, eschatology is “the study of the last things.” The term derives from certain Scriptural passages that speak of “the last days” (2Ti 3:1; Heb 1:2), “the last time” (1 Pe 1:20; Jude 18), “the last hour” (1 John 2:18), and other comparable statements. We find similar examples in the Septuagint, the second-century BC Greek translation of the Old Testament.
Theologians generally divide eschatology into two categories, cosmic and personal. “Cosmic eschatology” deals with the consummational history of the world system and the human race. It involves the study of the biblical data regarding the providentially governed flow of history as it develops toward its foreordained consummation. Cosmic eschatology especially focuses on the unfolding of God’s kingdom in history, the second advent of Christ, the resurrection of the dead, the final judgment, and the eternal state. “Personal eschatology” focuses on the destiny of the individual at death. This necessarily involves a study of physical death, the immortality of the soul, and the intermediate state. Of course, because it ushers the individual out of the temporal and into the eternal world, it also relates to heaven and hell. Eschatology as a whole asks the question: “What yet lies ahead, for both person and cosmos?” In this book I will focus on cosmic eschatology.
Although eschatological matters have been before the church for almost 2000 years, they have only in the last seventy-five years come to prominence as an area of systematic inquiry. Louis Berkhof noted in this regard: “When Klieforth wrote his Eschatologie, he complained about the fact that there had never yet appeared a comprehensive and adequate treatise on eschatology as a whole. . . In general it may be said that eschatology is even now [in 1941] the least developed of all the loci of dogmatics.” 
Near the same time, Charles Feinberg observed: “Eschatology remains a much neglected field of theological study and research. If one were to scan the standard work of theology, he would be surprised to find the little attention that is given to eschatology.”  Even more recently Millard Erickson can comment that the broader field of eschatology “has remained relatively undeveloped in comparison to such doctrines as the nature of the sacraments and the person and work of Christ.” 
The deficiency more recently, however, is not as bad as it once was. Unfortunately though, dominating eschatological inquiry are writers offering either rationalistic assessments (e.g., Rudolf Bultmann, Jürgen Moltmann, Wolfhart Pannenberg, Hendrikus Berkhof), dispensationalistic novelties (e.g., Charles C. Ryrie, John F. Walvoord, J. Dwight Pentecost), or sensationalistic prognostications (e.g., Hal Lindsey, Tim LaHaye, John Hagee). Today the lack has been greatly relieved by a growing body of important evangelical studies (e.g., Stanley J. Grenz. G. K. Beale, Cornelis Venema). Nevertheless, a careful, systematic, full-scale, current presentation of the optimistic eschatology of postmillennialism remains a genuine need within the church. I am presenting this revision of my 1997 second edition to fill this need.
Unfortunately, most evangelicals are still not familiar with postmillennialism, and many who are aware of it resist it as something “new.” Some lament the introduction of new ideas or the resystematization of older views in the eschatological marketplace of eschatology. One theologian writes that “we do not need another defense of a particular view of the future and certainly not a new view.”  Another comments in a review of a new work on eschatology that he “sincerely questions . . . the necessity of adding a fifth position to an already overcrowded rapture debate.”  Yet it is vitally important that we continue inquiring, systematizing, and correcting our understanding of this important field of theology.
1. Louis Berkhof, Systematic Theology, 664.
2. Charles L. Feinberg, Millennialism, 32.
3. Millard Erickson, Christian Theology, 1156.
4. Robert Lightner, Last Days Handbook, 93.
5. Gerald Stanton, “A Review of The Pre-Wrath Rapture of the Church” (Bibilotheca Sacra): 90.