Book excerpt: This collection contains hundreds of beautiful rarely-seen-before figures produced throughout the nineteenth century and the beginning of the twentieth century by famed father-of-modern-neuroscience Santiago Ramón y Cajal (1852-1934) and his contemporaries. Cajal was captivated by the beautiful shapes of the cells of the nervous system. He and his fellow scientists saw neurons as trees and glial cells as bushes. Given their high density and arrangement, neurons and glial resembled a thick forest, a seemingly impenetrable terrain of interacting cells mediating cognition and behavior.