Cover photograph (Copyright © 2012, American Society for Microbiology. All Rights Reserved.): A cartoon depicting a Bacillus thuringiensis spore labeled with a “barcode.” Such genetically barcoded B. thuringiensis spores are being utilized to detect and monitor the fate of spores in the environment. (See related article on p. 8272.) [NOTE: In the table of contents for this issue, the legend incorrectly lists Bacillus anthracis as the organism (753).]