Participant observation carried out with the agreement of the subjects being studied. This agreement may be tacit or formally expressed. In the latter case, the sociologist makes it clear that social science research is being undertaken, and the subjects themselves are then invited to give explicit permission for the research to proceed. In the former, the researcher also reveals his or her identity as an outsider, but states the purposes of the study less clearly, usually in the form of a general statement of interest in the subjects ‘in order to write a book’ about them. If this is sufficient to gain entry to the field, then no further details are offered to those being studied, unless specifically requested by the subjects themselves. Most researchers enjoy telling the story of how they gained entry to the field; indeed, often this is crucial to understanding the research, since the relationship that is established between researcher and subjects may well affect the quality of the data obtained. Most published accounts of overt participant observation therefore report in some detail on the observer's assumed role in the group or society being studied.