Necessary But Not Sufficient (2000) co-authored by eliyahu-goldratt, eli-schragenheim, and Carol Ptak, addresses a question that the success of the-goal made urgent: if TOC principles are so powerful, why do so many technology implementations — ERP rollouts in particular — fail to deliver the promised results?
The novel's answer is captured in its title. Technology is necessary but not sufficient. A new system may make previously impossible actions possible, but unless the organization also changes its rules, policies, and performance measures, the software merely automates old dysfunction faster. The constraint in most failed implementations is not technical; it is the set of assumptions and procedures built into the organization's existing ways of working.
This thesis extends theory-of-constraints into the domain of organizational change management and positions TOC's thinking-processes as the right tool for identifying which rules must change when technology changes. The novel is less widely read than Goldratt's other works, but its core insight — that technology and process change must co-evolve — has become central to how serious TOC practitioners approach enterprise-level implementations. It belongs to the domain-expansion-era when Goldratt was systematically applying TOC reasoning to every major business function.