Cover photograph (Copyright © 2007, American Society for Microbiology. All Rights Reserved.): Phenazine pigments produced by Pseudomonas species come in all the colors of the rainbow. These natural products, long known for their toxicity to other organisms, are now garnering attention for their physiological effects on their producers. The following crude and purified preparations of phenazines from P. aeruginosa and P. aureofaciens cultures are pictured (left to right): aqueous solution of pyocyanin, pH ~2; 2-hydroxyphenazine in acetonitrile; aqueous solution of 2-hydroxyphenazine and phenazine-1-carboxylic acid, pH ~2; supernatant from a P. aeruginosa LB culture containing pyocyanin, phenazine-1-carboxylate, and 1-hydroxyphenazine; aqueous solution of pyocyanin, pH ~7. (See related article on Page 6372.)