Introduction: the predictable-unpredictability of the world -- Complex models: radical challenge to management orthodoxy -- Complex action: the uncertain outcomes of individuals negotiating in groups -- The complex self: the 'I', 'me' and 'we' -- Complex communication: persuading and being persuaded -- Complex knowledge, complex knowing -- Complex authority: the leader in the group and the group in the leader -- Complex ethics: widening our circle of concern -- Conclusions: towards greater humility and humane ways of working.