1: Complementarity in systems modelling / Michael Pidd -- Systems modelling -- Messes and wicked problems -- Hard and soft approaches -- What do we mean by complementarity? -- References -- 2: Insights from complexity: organisational change and systems modelling / Michael Lyons -- Introduction -- Complex adaptive systems and complexity -- Complexity and management -- Working with systemic problems -- The simulation of complexity -- Conclusion: complementarity intrinsic to complexity? -- References -- 3: 'Classic' or and 'soft' or - an asymmetric complementarity / Peter Checkland and Sue Holwell -- Introduction -- Classic or methodology -- Soft systems methodology -- 'Hard' and 'soft' perspectives -- The relation between 'hard' and 'soft' perspectives : an asymmetric complementarity -- Conclusion -- References -- 4: The effectiveness of high dependency care / Roth Kowalczyk -- Introduction -- The issues -- Effective high dependency care provision -- Methods and methodology -- Analysing the introduction of high dependency care -- Effects -- Conclusions -- References -- 5: Complementarity in practice / George Paterson -- Introduction -- Organisational setting for or/ms practice -- Types of assistance available -- Or/ms in relation to other consulting offerings -- Models and modelling -- Examples from the oil and gas industry -- Complementarity of hard and soft -- References -- 6: The complementary use of hard and soft or in developing tax policy / Joyce Brown and Ceri Cooper -- Introduction -- Background -- The hard or in the tax study -- The soft or -- Complementarity -- Acknowledgements -- References -- 7: Mental models and learning in system dynamics practice: john morecroft -- Introduction -- Mental models, transitional objects and formal models -- Models of business and social systems -- The BBC World Service modelling project -- The impact on managerial thinking of the World Service project -- Discussion -- References -- 8: Using causal mapping - individual and group, traditional and new / Fran Ackermann and Colin Eden. -- Background to mapping -- Modes of use -- Applications of mapping.