Cover legend: Bundles of axons in an autistic individual, reconstructed in three dimensions from serial electron microscopic images. Medium-sized axons (magenta) in the anterior cingulate cortex in the autistic brain show more branching than those in control brains. Axon branches are color coded by size of the parent axon (small: cyan; large: yellow; extra-large: black). For more information, see the article by Zikopoulos and Barbas in this issue (pages 14595–14609).