While this chapter considers the relevant research literature, its focus is on the practice of interviewing vulnerable people. That is to say that it is intended to be of practical use to interviewers. After briefly discussing the nature of ‘vulnerability’, it considers what interviewers should think about when planning, preparing for and conducting interviews with vulnerable people. It goes on to explore the issues specific to interviews with witnesses and with people suspected of committing crimes (suspects) before discussing some of the limitations surrounding the implementation of good practice. Finally, it looks at the implications for training that follow from the preceding sections. Prior to that, however, it is worth considering the developments that have led to the current and ongoing concerns with vulnerability in the criminal justice system of England and Wales that may have international as well as national implications.