We need to be grateful to Google Books for making material available gratis. Today I learned again just how much a library can charge for a photopy. When I was still looking for a copy of Hart’s 1749 translation of Herodian, I contacted several libraries who had one (located using Copac) and asked. The British Library wanted around $200. Aberdeen University have just managed to come up with a similar and slightly higher price. It makes you look differently at each PDF on Google Books, doesn’t it?