This position paper outlines a number of key questions concerning BIM (Building Information Modelling), as well as the arguments and the historical background behind them. These include the incomplete theory of BIM, the reasons for the emergence of understanding BIM as a panacea for all ills in AECO (architecture, engineering, construction and operation of buildings), the relation between BIM promise and BIM performance, some of the key misconceptions and misunderstandings concerning BIM, and fundamental concerns about what is assumed to be the future of BIM. The paper concludes by suggesting four themes for further discussion and research into the nature and future of BIM and of AECO computerization in general: BIM theory, implementation, the view from practice and legislation / policies.