This chapter focuses on the development in England (and later elsewhere) of an interviewing procedure that seeks to gain valid information from suspects without being oppressive. It will then provide an overview of research on its effectiveness, noting that some (e.g., long-established training organizations in the USA) find this difficult to believe and suggest it is a “tall story.” In 2018, the highly experienced ex-police detective O’Neill commented: “Whenever criminal investigation practice is discussed … credibility problems will arise if there is little evidence to underpin practice, training and development.” This chapter contains such evidence.