It is now rather over a century since the marble statue of a youth in Naples was recognised as a copy of the Doryphoros of Polykleitos, and the first attempt made to extract from it the mathematical principles of the Polykleitan canon. Periodic warnings uttered on the subject by such scholars as Gardner and Furtwängler failed to deter further speculation, which culminated in Anti's monumental publication of 1921. Understandably enough, this seems effectively to have checked research in the field, with (...) only one or two exceptions, for a number of years. In the past decade or so, however, the pendulum, apparently never stable for long, has swung back again: a spate of books and articles on Polykleitos and his school has appeared, including no fewer than four major attempts to recover the principles of the canon from the surviving copies of his works. Again, murmurings to the contrary have passed unheeded, the gulf between believers and unbelievers now, it seems, having become virtually unbridgeable. With this in mind, and considering that Polykleitan studies have undergone a quiet revolution in the last year or two through the identification of fragments of casts of the Doryphoros and an Amazon among those recently discovered at Baiae, it seems an opportune moment to try to restate a few principles, basic but all too often ignored, and to indicate a number of directions that further research might take. (shrink)