Why a new edition of John of Salisbury's Metalogicon? What was so very bad about Clement Webb's edition of 1929 that it needed to be replaced? The answer is that while Webb did sterling service in identifying John's sources, he had little idea of how to produce a critical edition of John's text. In fact, while claiming to use three contemporary or near-contemporary manuscripts, he merely reprinted the text of J.G. Giles (1848), itself dependent on previous editions, correcting Giles only here and there from a cursory inspection of his primary manuscripts.
The present edition is based fairly and squarely on all the oldest surviving manuscripts, and aims to give a text as close as possible to the original, emending the consensus of the manuscripts where that is deemed not to be authentic. The introduction discusses the manuscripts and the manuscript tradition, describes the printed editions, and outlines the principles of spelling and punctuation followed in the edition. Underneath the text on each page are two apparatuses, one of variant readings (most of them not recorded at all by Webb), the other of John's sources (most of them already present in Webb's annotation). There are three appendices: of authors cited, of proper names, and of orthography.
The fidelity of this new text to the surviving manuscripts (which have been repeatedly collated and examined for the purposes of this edition) makes it the definitive text of this important treatise on education, in particular the study of dialectic, in the twelfth century.