Future expectations and promise are crucial to providing the dynamism and momentum upon which so many ventures in science and technology depend. This is especially the case for pre-market applications where practical utility and value has yet to be demonstrated and where investment must sustained. For instance, clinical biotechnology (including a wide range of genetic therapeutic and engineering applications) has been at the centre of ferocious debates about whether or not promises and expectations will be realised. In some cases, the failure of expectations has severely damaged the reputation and credibility of professions, institutions and industry. The need for a better analytical understanding of the dynamics of expectations in innovation is both necessary and timely. This paper develops the basis for a sociology of expectations, drawing on recent writing within Science and Technology Studies (STS) and case studies of biotechnology innovation. In particular, we offer a model for understanding how expectations will predictably vary according to some key parameters. Such factors include the degree to which technologies and innovation relationships are either relatively established or newly emergent. Expectations will also vary according actors’ relative closeness and involvement in knowledge production itself. The paper proceeds by analysing the way expectations in clinical biotechnology have changed over time. That is, we compare the way the future was once represented with the way it has been represented more recently. The paper concludes by offering a means by which it is possible to map or model the situatedness of expectations.