This paper illustrates how recent tragedies have been shown to be threatening to the medium-term sustainability of organizations designed and developed solely on the basis of short-term efficiency gain. Over the past 30 years, Western organizations have institutionalized this emphasis on efficiencies through the implementation of Japanese management philosophies, such as lean thinking. This situation has assisted the removal of vital adaptive and responsive capacity or 'organizational slack', necessary for organizations that need to contend with complex and dynamic environments. The authors argue for the need to challenge managerial mindsets and re-engage a pluralist metaperspective both at the level of strategic purpose and organizational configuration. In particular, it suggests that, in addition to the efficiency model, a complementary and to some extent alternative set of 'high-reliability' organization (HRO) design principles are required. They focus on the notion of creating an HRO that privileges integrity in the achievement of medium- and long-term goals over short-term efficiency gains. Integrating both 'lean thinking' and 'high-reliability' principles is a requirement for post-modern managers operating in their roles as organizational engineers, if mission accomplishment is to be realized.