Visual cortex has been an excellent model system for developing a quantitative understanding of brain function. We understand a great deal about the physical signals that initiate vision, and this knowledge has led to a relatively advanced understanding of the organization of major structures in visual cortex. This talk will begin with an explanation of the neuroimaging methods that are used to measure a major organizing feature of human visual cortex: visual field maps (also called retinotopic or visuotopic maps). The talk will also describe new ideas about quantitative modeling of these signals, and how these models are leading to a new understanding of the organization of brain computations for seeing. Finally, there are promising new MR methods for identifying the connections between different parts of the human brain. I will introduce the methods and technical issues concerning how we can measure these pathways during development. A great many labs have shown that the properties of these ‘wires’ (bundles of axons) are correlated with the development of skilled reading. Understanding how the development of these wires influences human cognition is becoming increasingly important as we learn about how human brain produces thought.