It is far too early in the morning, and Bonnie L. Bassler is charging across the Princeton University campus, incandescent purple coat flying, brown curls bouncing, big laugh booming. She has come directly from the aerobics class she teaches every morning at 6:15--"I get up at exactly 5:42, not a minute earlier, not a minute later," she says emphatically. She says most things with similar energy, and when the conversation turns to her work, she becomes, impossibly, even more dynamic. "I am not meant to be stopped in time," she laughs. "I am supposed to be a blur." The 41-year-old Bassler--a professor of molecular biology, winner of a 2002 MacArthur Foundation genius award, and occasional actress, dancer and singer--studies bacteria and how they communicate among their own kind and with other species. Quorum sensing, as this phenomenon is called, is a young science. Until recently, no one thought bacteria talked to one another, let alone in ways that changed their behavior, and Bassler has been instrumental in the field's rapid ascension. She has figured out some of the dialects--the genetic and molecular mechanisms different species use--but is best known for identifying what might be a universal language all species share, something she has jokingly referred to as "bacterial Esperanto."