His audience: more than 100,000 world-class experts in science -- but not necessarily expert in the kind of science he writes about. It's a challenging beat, because his readers are knowledgeable, savvy, and skeptical. Since science papers often come with a backstory that he frequently reviews in his articles, he must analyze and critique the quality of the work on its own merits and put it into context for the field. Kerr wrote in A Field Guide for Science Writers: "If, as veteran San Francisco Chronicle science reporter David Perlman once wrote, science writing is a continuing graduate education, then writing for scientists is a Ph.D. in science news reporting."