It may seem audacious, in light of A. S. Pease's monumental commented edition of De natura deorum, for another English work to be offered to the public dealing with a portion of that text. Pease's diligence in collecting relevant literature, primary and secondary, make his volumes an unrivalled treasure-house of information. However, it must be said that students reading N.D. for the first time often find that Pease's work fails to provide accessible answers to the puzzles that perplex them. In not a few cases Pease declines to adjudicate on controversial points, contenting himself with his massive citations; but students tend to lose their way in these thickets and return from their expedition disappointed. Furthermore scholarship on N.D. has been going forward since the mid-50s, especially on philosophical points, where, even by standards of his day, Pease was less than sure-footed. On the text, too, progress has been made, in particular P. L. Schmidt's reassessment of the Leiden corpus; hence Pease's stemma (a modification of Mayor's) is superseded, the major problem being the insufficient weight he gives to codex B (see the Introduction §7). Though capable of emendation (cf. on §28), Pease produced a text that is conservative sometimes to the point of unintelligibility (e.g. §§1, 39); he tended doggedly to defend the transmitted text and not consider whether scribes might have fallen into errors that obliterated the required philosophical sense (cf. on §§28 and 89). Moreover, in technique Pease's commentary was conservative even by the standards of its times.