Because they're written on bark, Gandhari manuscripts are much more fragile than anything on paper, or vellum. A French archaeologist who discovered some in the 1830s found that they literally crumbled to dust as soon as he touched them. Rolled up, the manuscripts Salomon saw resembled enormous cigars. Unrolled, some of them were more than 8ft long. As he gazed at them, something strange happened. "Literally, it was as if my life flashed before my eyes." Straight away, Salomon realised that there was so much new material here he was going to be spending the rest of his career working on it. Sure enough, 20 years on, he's still hard at it. "I know a lot more now than I did, but there's still a long way to go."