The November issue of Nature Neuroscience is a special issue on big data in neuroscience. Subjects include: different kinds of big data in neuroscience, from epigenomics to connectomics and whole-brain activity recordings to big behavioral data. The authors of these pieces tackle tough questions that have come to the forefront during this era of big data, including whether big data will completely change the way neuroscience is done, how much insight will be gained from big data, and what are the best ways to go about conducting such projects.