This book has brought together leading investigators who work in the new arena of brain connectomics. This includes `macro-connectome' efforts to comprehensively chart long-distance pathways and functional networks; `micro-connectome' efforts to identify every neuron, axon, dendrite, synapse, and glial process within restricted brain regions; and `meso-connectome' efforts to systematically map both local and long-distance connections using anatomical tracers. This book highlights cutting-edge methods that can accelerate progress in elucidating static `hard-wired' circuits of the brain as well as dynamic interactions that are vital for brain function. The power of connectomic approaches in characterizing abnormal circuits in the many brain disorders that afflict humankind is considered. Experts in computational neuroscience and network theory provide perspectives needed for synthesizing across different scales in space and time. Altogether, this book provides an integrated view of the challenges and opportunities in deciphering brain circuits in health and disease.