This essay demonstrates how Charles Dickens used the form of serial fiction to experiment with a uniquely Victorian idea of life as a dynamic network of interactions. Reading Our Mutual Friend alongside nineteenth-century physiological and evolutionary writing, I show how Dickens shaped novel form around the attractions and reactions that organized social and psychological life in his city. Victorian sciences—particularly the work of George Henry Lewes and Charles Darwin—were turning to “net-work” to describe the plastic processes underpinning biological life. Dickens's fiction used the same dynamic potential of network form to put in motion the mechanisms of social life. Taking a novel form traditionally organized around the story of a self, Dickens used serial publication to incorporate variety, change, and new combinations of radically heterogeneous characters into each new installment, turning novel form into an ongoing formation. The resulting model of character psychology is one that replaces interiority with interaction and individuated desire with physiological affect.