As the prices commanded by landmark works and artists rise ever higher, so too does the sophistication of forgeries being produced to dupe collectors and institutions. A tip_Ñ_itÕs apparently far easier to copy a Modigliani than a Leonardo_Ñ_at a recent exhibition of his work, 20 out of the 21 works on display were found to be counterfeits. This piece profiles the man said to be the very best in the field of science-led authentication.