Christian Raetz: scientist and friend extraordinaire.

Chris Raetz passed away on August 16, 2011, still at the height of his productive years. His seminal contributions to biomedical research were in the genetics, biochemistry, and structural biology of phospholipid and lipid A biosynthesis in Escherichia coli and other gram-negative bacteria. He defined the catalytic properties and structures of many of the enzymes responsible for the "Raetz pathway for lipid A biosynthesis." His deep understanding of chemistry, coupled with knowledge of medicine, biochemistry, genetics, and structural biology, formed the underpinnings for his contributions to the lipid field. He displayed an intense passion for science and a broad interest that came from a strong commitment to curiosity-driven research, a commitment he imparted to his mentees and colleagues. What follows is a testament to both Chris's science and humanity from his friends and colleagues.