This is the first comprehensive study for nearly 200 years of what remains of the writings of the Presocratic philosopher Philolaus of Croton (470-390 B.C.). Professor Huffman presents the fragments and testimonia with accompanying translations and introductory chapters and interpretive commentary. He produces further arguments for the authenticity of much that used to be neglected, and undertakes a critique of Aristotle's testimony, opening the way for a quite new reading of fifth-century Pythagoreanism in general and of Philolaus in particular.