BIOPHYSICS. For the article “Microviscometry reveals reduced blood viscosity and altered shear rate and shear stress profiles in microvessels after hemodilution,” by David S. Long, Michael L. Smith, Axel R. Pries, Klaus Ley, and Edward R. Damiano, which appeared in issue 27, July 6, 2004, of Proc. Natl. Acad. Sci. USA (101, 10060–10065; first published June 25, 2004; 10.1073/pnas.0402937101), the first two authors, David S. Long and Michael L. Smith, contributed equally to this work.