This paper presents a systemic intervention methodology that starts with boundary critique: exploring different boundaries and values that might matter to stakeholders when framing the purposes of an intervention. Boundary critique helps people develop an enhanced understanding of the situation being addressed, and it focuses attention on dealing with conflict and marginalization. Systemic intervention also offers a theory and practice of methodological pluralism: creatively mixing methods from a diverse range of methodological sources in response to the initial boundary critique, so systemic improvements can be designed. This creative mixing of methods yields a much more flexible and responsive approach than might be possible with a narrower range of methods. The value of a systemic intervention approach is illustrated through several practical examples.