The human brain has been studied for millennia, but in the past decades huge advances have occurred in neurology that have allowed scientists to reassess what we really know about the least understood part of the human body. We can now observe the activity of the brain as it performs different functions. We can also use scanning technology to chart the neural pathways and devise maps. The explorations have revealed surprising results. The Britannica Guide to the Brain is a valuable resource of the most up-to-date ideas of our times.