As a culture reporter working on a book about medicine, I marvel at writers who are equally at ease in the idioms of science and literature?dual citizens, as it were, of C.P. Snow's two cultures. This group is undoubtedly small, and the achievements of its most heralded members, Primo Levi and Lewis Thomas, arguably remain unsurpassed. But among its number today, Barbara Ehrenreich?who spent her adolescence mulling over Conrad, Dostoyevsky, Nietzsche, and Camus, and earned a doctorate in cellular immunology before embarking on a career as a feminist muckraker?may rank as the writer most consistently bracing to read.

In her latest book, the underappreciated Living With a Wild God, Ehrenreich subjects a youthful mystical experience?she can hardly stand the term?to unflinching clinical appraisal. Her essay ?Terror Cells,? in the current issue of The Baffler, takes the opposite tack. Here her subject is the curious behavior of macrophages, immune cells that have recently been shown to go rogue under certain circumstances, colluding with, rather than attacking, cancer cells, for example. But her real concerns are metaphysical: In what respect are cells also ?selves,? capable of acting on their own? Has science?s reductionist fixation on ever smaller pieces?on molecules rather than cells?blinded it to the possibility of cellular ?individuality? and to potentially consequential insights that might follow? You won?t find these kinds of questions in the pages of Nature.