What we can and cannot tell about the wiring of the human brain.

It was 20 years ago that Crick and Jones lamented the fact that human neuroanatomy was backward. They would be astonished to read the contents of this issue. At that time they had not foreseen what could be achieved by the combination of diffusion imaging and the study of resting state covariance. This paper assesses what can and cannot be done with the methods that we now have.