ball has written a book on not just the church but about medieval history, scholasticism, masonry etc. he dismisses the superstition that the chuch is a pagan or druidic place an consequently advance all of the most rational explationations for odd symbols in the church (some were used to denote which craftsmen made which pillars etc. others were used to designate where in the church to put the individual slabs and pillars).
the book is scientific, well written and recapts the views of many other serious authors. as i said it is as much a broad history of northwestern europe in medieval times as it is about the church itself. the only weakness to the book is that it is rather inconclusive but then again, such is the state of medieval scholarship concerning the topic as this time