In the northeast regional office of a large bank, four Vice Presidents in three years have run the facility. Business has sagged. Employee and management turnover have increased to such a level that Headquarters have announced plans to close the office and distribute employees elsewhere. “Why does this keep happening to us? What is going on here?” The airport bookstores brim with can-do solutions to address such challenges: better leadership, clearer mission and strategy, restructuring, system-wide training programs and HR interventions. Many organizational dilemmas can, seemingly, be fixed by charismatic leadership, top-level planning meetings, a cascade of memos and training programs, the roll-out of tasks, and the measurement of outcomes. The market rewards immediate results – then the charismatic leader may leave and the changes do, too. This article examines how foundational knowledge of theory and practice can prepare an OD practitioner to support clients in such situations. It describes a more comprehensive perspective on transformational change: the Organization Development (OD) approach; focusing in particular on the core knowledge base for effective OD practice. OD’s roots are in the legacy of World War II in the United States (and later in Northern Europe), where trauma of world war and the return of soldiers heightened focus on democracy, fascism, compliance, coercion, group dynamics, leadership, civil rights, gender equality, diversity and race relations. OD emerged as a values-conscious field of applied behavioural science where a skilled practitioner works with people in organizations to design and implement sustainable change. Always focusing on the dynamic human system, OD practitioners build collaborative relationships with clients and engage in data gathering and sense-making which enables clients to make changes that maximize creativity, performance and return on investment.