I recently came across a post (http://duckdown.blogspot.com/2006/01/outstanding-questions-on-rules-engines.html) from James McGovern dating back to the beginning of the year is which he had asked a number of questions about Rules engines. As Rules engines have become a subject of some interest to me over the last eighteen months or so, I though I would have a go at providing some answers. In my own inimitable style, I of course wrote far too much to be accepted as a comment on James' web site (sorry, James)! So I've expanded my replies a bit more and posted them here at http://geekswithblogs.net/cyoung/articles/76795.aspx. I hope they are of some interest.