Background: The Approaches to Teaching Inventory (ATI) is structured as two main scales, reflecting a teacher-centred information-transmission approach versus a student-centred conceptual-change approach, each subdivided into intention and strategy subscales. Its use in higher education investigations is increasing and, by default, it is assuming an operational definition of variation in "approaches to teaching". However, the ATI's conceptual foundations and procedures of development have not been systematically scrutinized. Aims: The present paper presents a comprehensive historical review and critique of the ATI's development. Method: The procedures applied in the ATI's initial development are critically evaluated. Close attention is paid to the source of its foundation item pool, the criteria used in selecting from those foundation items, the adequacy of subject samples used in item trialling and the uses made of resultant trial response data in determining the final form of the inventory. The historical record is examined closely to determine the conceptual and psychometric credibility of the instrument. Conclusions: There are serious and irreversible concerns with the rigour and methodology adopted in the psychometric development of the ATI. The ATI manifestly does not reflect a functionally useful range of "approaches to teaching", and its application to activities connected with the professionalization (and evaluation) of university teaching is rejected.