A way of treating interests which differs from those of both Woolgar and Barnes is here recommended. This third `enrolment' or `networking' theory approach notes that actors attempt to enlist one another in a variety of different ways, including the transformation of imputed interests. Some of the strategies adopted in this process are considered. Overall, it is suggested that interests should not be imputed to actors as background causes of action, but rather that they should be seen as attempts to define and enforce contingent forms of social order on the part of actors themselves.