The conscientious commentator will offer his work to the public in a mood of doubt and self-questioning. As an Editor of the series in which this edition appears I have felt a special duty to keep in the forefront of my mind its declared aim: ‘to provide the student with the guidance that he needs for the interpretation and understanding of the book as a work of literature’. The amount of guidance here provided may, however, strike some readers as excessive. If so, it is because it has seemed to me that in the past Lucretius’ interpreters have not always taken enough pains to disentangle and follow his argument as he intended it to be followed, and this, whatever shortcomings may be found in the execution, is what I have attempted to do. The De Rerum Natura, in spite of the lucid style of which the poet was rightly proud, is a difficult book, and I have often preferred the risk of telling the reader what he already knows to that of leaving him in the lurch – the besetting sin of commentators. It may also be felt that there is here too much expatiation on the poetical techniques of Lucretius. In this department the existing commentaries seem to leave much to be desired. In spite of the lead given by H. Sykes Davies in his Criterion article of 1931–2 and in spite of more recent contributions in this field such as Professor David West’s excellent The imagery and poetry of Lucretius (1969), the conventional idea of Lucretius’ art still persists: ingenio maximus, arte rudis. Cicero knew otherwise; but posterity has yet to be convinced. The student who finds some notes inordinately long may care to note that an effort has been made to, so to say, ‘grade’ their contents so that the essential information is usually presented at the beginning.

Two considerations have prompted the thought that a second edition of this book may not be unwelcome. As informed interest in Lucretius has continued to grow – a fact strikingly illustrated by the number of translations that continue to appear – so it must be accepted that students now come to him less well prepared linguistically than was the case in the 1970s. Accordingly the Commentary has been extensively revised and enlarged, with, it is hoped, due account taken of the comments of reviewers – though my old friend and critic Professor David West would now miss in the notes the ‘brevity that comes close to wit’ that he admired in the first edition.

Three passages in the Introduction to the first edition have called for reconsideration: what was said there about the ‘middle’ or ‘florid’ style of oratory, the discussion of the diatribe and what is said about the spelling of seorsum. These points are dealt with at p. 13 n. 51, p. 14 n. 55 and p. 18 n. 73 respectively. The section on the text has been rewritten in the light of subsequent work in that field, especially that of Professor Michael Reeve and Dr David Butterfield, to both of whom I am greatly indebted for help and advice generously given. The apparatus criticus has also been revised in accordance with Dr Butterfield’s advice. Otherwise the Introduction is reprinted unaltered apart from a handful of additions to the footnotes in addition to the three noted above, and adjustment of the references to the secondary literature in conformity with current series style. In the Supplementary Introduction I have confined myself for the most part to comments on such post-1971 contributions to Lucretian studies (some of which are in any case noticed in the revised Commentary) as seem likely to be useful to readers of this book of the De Rerum Natura. I regret that it has not been possible to include references to all the important work of Professor Ferguson Smith on the Oenoanda inscription.