A new book that captures recent proceedings on this disputed portion of the Gospel of John is in preparation.
In many modern Bibles, John 7:53-8:11 is bracketed off or placed in the foot not section of the page. The absence of this pericope from some important early witnesses makes it suspect in contemporary scholarship. Although, as David Black notes, the Vetus Latina attests to the pericope in the second century. Theories that either liturgical exclusion or ecclesiastical suppression impacted the textual tradition of the pericope need careful evaluation.
Liturgical exclusion is not impossible. Christianity could have inherited something of Judaism's sense that certain texts were not appropriate for public or liturgical use and best left for restricted reading. The book of Ezekiel once fell into this category.
Ecclesiastical suppression is possible if we run with Erhman's theory of the "orthodox corruption of scripture." This said, Erhman tends to run a little wild with his allegation of ecclesiastical corruption of the text. The majority of instances are relatively minor; John 7:53-8:11 would be an exceptional instance.
To complicate things further, the grammar and syntax are well within the parameters set by the ancient author. It is either from the ancient author or from someone capable enough to mimic his style. If it is authentic, then there would appear to be an unresolved issue surrounding the early transmission of John's gospel. The manuscript tradition would have diverged at an extremely early stage. This, however, reminds one of Raymond Brown's earlier and somewhat more convoluted hypothesis concerning the development of the Gospel of John - extremely fine proposals have to be viewed with caution.