Proponent of an "ancient " system of enchantment (a.k.a. understanding of the world) lost at the end of the ancient world but leaving traces on the landscape and in myth. (see wikipedia)
Fellow re-discoverer of the system of ancient metrology with the publication in 1982 of Ancient Metrology, a booklet making sense of the Great Pyramid, Stonehenge and an early division of units of measure into (a) Modules such as the Roman, Greek, Jewish, Egyptian, etc as having (b) microvariations he called Southern and Northern because they corresponded to the ratio of 176 in the north ( the 51 degree mean earth degree) to 175 in the south (lat 10 degrees). This was eventually expanded by John Neal in All Done With Mirrors, into a system of microvariations found within historical measures, based (at least*) on 176/175 but also 441/440 which Michell had shown as the ratio between the polar radius and mean radius of the earth. Combined these give 12 6/125, the ratio enabling the doubling in volume of Apollo's cubic altar and do important things with regard to circular measures also. Michell's final statement on metrology is to be found in his updated The Dimensions of Paradise where he applies metrology to his overall world view where metrology meets music, monuments and many geometrical forms he believed lay behind the form of the world.
*for instance, the microvariation ratio of 225/224 has been found by Neal in Arabic works.
Michell worked also with Robin Heath as presented in The Measure of Albion, plus extra work from either author on landscape geometries within the British Isles - extending their The View over Atlantis and Sun, Moon and Stonehenge.
Author of the charming and informative Little History of Astro-Archaeology