Anyone who frequents photographic sites on-line or picks up a current book on photographic composition knows about the “Rule of Thirds”. The funny thing to me is that as pervasive as it seems to be, that having been an active photographer since 1978, I never heard of it before 2005 when I first visited this site. And that in light of the following facts: Early on, I subscribed to Consumer/Amateur photo publications and remember no mention of it. I have a Petersen’s Photographic book “Basic Guide to Photography” from that time period (1973) that has a very good section on Composition but no mention of the Rule of Thirds. A 2000 Amphoto book, John Garrett’s Black and White Masterclass, that has several chapters on compositional considerations but no mention of it. I also have several other books from the 80's and 90's on commercial photographic topics that never mention it. I took art classes that covered the principles of Design and Elements of Art in the early 80's and there was no mention of it. In fact, I have yet to find a textbook on art that includes it or even mentions it. I took photo classes at an art school, also in the early 80's and no mention of it. I have taken workshops during the 80’s with the likes of Ansel Adams, John Sexton, Jerry Uelsmann, Richard Misrach, Linda Conner, Frank Goelke, all great photographic educators—guess what, no mention of it. I taught photography in the early ‘90’s at an accredited Art College and no where was it in the curriculum nor was it ever mentioned. And with 25 years of working with top art directors and designers from around the country creating images for them, there has never been any mention of it—even though we obviously discussed the design considerations of hundreds, maybe thousands, of images. I have even asked some of them if they heard of it, once I had, and the answer was always “no”. I checked the internet and Wikipedia gives a resource from 1750, a copy of which I have obtained, that is supposed to be the first codification of the term—although there is no mention of a Tic-Tac-Toe Grid or the magic intersections that are so frequently referred to on Photo sites. So where did it come from and when did it get into the vernacular of the amateur photographer? Certainly, it didn’t sleep for 250+ years since one person made the observation and then magically appeared as a well defined grid sans many of the other elements of proportion described in that original manuscript. Most principles of composition have a well defined and scholarly vetted lineage while this one, seemingly held in such high regard by so many, seems to have materialized sometime in the last 8-10 years out of the ether. Can anyone help?