Cover legend: The human enteric nervous system contains ~500 million neurons in 20 functional classes. All of these cells form from a small population of neural crest-derived cells that migrate through the bowel and vigorously proliferate before differentiating and extending neurites. This image shows a whole-mount preparation of the mouse small bowel myenteric plexus after NADPH diaphorase histochemistry. For more information, see the article by Vohra et al. in the August 29, 2007 issue (pages 9458–9468) (http://www.jneurosci.org/cgi/content/abstract/27/35/9458).