My copy delivered today, and pix are superb and looks to be an easy and interesting read...........and, unlike some, it's light enough to read in the bath.
Having been personally guilty of mis-understanding the cause of the 'Y' and 'T' marks on the underside of many later C19 lower grade examples of drinking glass, it appears I wasn't alone in being in error.
Having read very briefly some of the picture captions, I notice that Tim Mills states that these marks were the result of the use of the gadget (rather than the shears as Peter has indicated). "Beneath the foot is a gadget mark in the shape of a Y. This was left by a mechanical rod used to grip the foot, being a replacement for the pontil iron."
My only other casual observation (since I've not yet read the book - I have to wait until bath day), and being interested in pressed glass, would be that I'd like to have seen greater coverage of pressed material from the second half of the C19. However, perhaps Tim has that in mind for his second volume