This is a fascinating thread for me, but also frustrating because I was on Ian's site last week and this week it is gone. (All the domains associated with him are now down. Does anyone know any contact details for whomever used to maintain the sites?)
Doubly frustrating is the fact that I have only just signed up here, and just begun to get back into pottery after a long hiatus. In the meantime I will find his books and begin to experiment, as I am trying to find options for a difficult-to-glaze black stoneware body.