This chapter defends the existence of negligence, understood here as a form of inadvertent moral wrongdoing for which the wrongdoer is presumptively and non-derivatively responsible and blameworthy. The wrong in question is failure of due care. This common-sensical claim needs defense in view of widespread skepticism about the possibility of non-derivative inadvertent wrongdoing. A major source of this skepticism is the conviction that all wrongdoing must ultimately derive from intentional or knowing violations.