This book is the English translation of Sebastiano Timpanaro, La genesi del metodo del Lachmann, Firenze 1963. Timpanaro's leading book traces back the history of the method of editing texts which still today is named from Karl (Carl) Lachmann's (Lachmann's method, or Lachmannsche Methode). Lachmann was one of the leading German classicists (and as a distinguished Germanist made relevant editions, too, of many Middle High German poets: see also Karl Lachmann. Eine Biographie, by Martin Julius Hertz, 1851). In 1850 he published his edition (text and commentary) of Lucretius, De rerum natura (Lucretius wrote in the Late Republican Rome, at the middle of 1st century b.C., the most important Latin work about Epicurus' Perì phýseōs and among the most important ones, with the Georgics of Virgil, in Latin didactic poetry). Lachmann's edition and commentary were the principal occupation of his live from 1845 and are the founding work of 19th century classical philology and modern textual criticism; while drawing the stemma of the older extant MSS of Lucretius with a rigidly scientific recensio Lachmann succeeded in tracing back the lost archetype of the De rerum natura (written during the Carolingian Renaissance). Timpanaro's book was first published in 1963 and had many other revised Italian editions; French ed. La Genèse de la méthode de Lachmann, Paris 2016.