A history of critical editions of the Greek New Testament and the methods developed to create them coincide with virtually the entire history of New Testament textual criticism. Thereby, Karl Konrad Friedrich Wilhelm Lachmann's Greek text became the first to be recognised as a decisive break from the textus receptus, which in some form stood at the head of the pages in virtually all preceding editions. This chapter explores Lachmann's text-critical criteria in systematic fashion. A new tool, the Coherence-Based Genealogical Method, developed by Gerd Mink in Münster, is currently being refined for assessing relationships among the texts in all of extant New Testament manuscripts by a highly sophisticated computer program that, by employing the present array of external and internal criteria, constructs a local stemma for each place of variation. Reasoned Eclecticism has a history that began with the first discussions of canons of criticism, accompanied by refinements along the way.