Extensive revision 

Over the past day, someone has made extensive revisions to this article: here is the diff. There appears to be some excellent work in it, which is the very best reason to assume good faith, but I have had to revert it, and want to explain why here. First of all, I hope the anonymous editor who wrote the other version reads this; if you do, may I encourage you to create an account, which will enable easier communication, and may help me and other editors guide you in learning how best to use Wikipedia. 

The most pressing reason to revert the changes is because the substituted version contains no inline references, but only a list of books and papers at the end. As I don't have access to these, I can't (even if I had the time) go through them and add page references to each sentence or paragraph. Also, although this is more easily rectified, the substituted version contains not a single wikilink, which makes it difficult for the reader to get a sense of context. Wikipedia is built on internal linking. 

It is also built on collaboration between editors. The substituted version was, as far as I can see, a complete rewrite, taking no account of the previous work done. I hope that the future can see more productive collaboration, because clearly this anon editor has some superb sources to refer to, and  I have no doubt  a great deal of goodwill as well, as do I.