Mapping the brain is an unenviable task with a staggering scale of complexity. The first step in the venture took stock of the brain’s hardware—the types of neurons that form the basis of neural computation. The second traced where neurons branch out to connect with others—either immediate neighbors or far-off partners across brain regions. For connectomics, the next sprint forward is less about hardware and more about hard questions: what can brain maps actually tell us about how the brain works?