Contents

25 March 2005
Vol 307, Issue 5717

About The Cover

Cover image expansion

COVER A colored barium x-ray image of the colon of a patient in the early stages of Crohn's disease. A special section explores the diverse biology of our gut, including the abundant yet largely unknown microorganisms it harbors, its normal functions of digestion and delivery of nutrients, and diseases to which it is prone. See page 1895. [Image: Gjlp/Photo Researchers Inc.]