This text was written as part of the project Modelling of Complex Systems for Public Policy. It reviews the classical authors who jointly contributed to establish the elements of what could constitute a "science of complexity". Based on the original writings of these authors, the text discusses...

Complex systems' approach and methodologies emphasize interactions, diversity and dynamics. Complex systems perspectives also enable public policies to be considered comprehensively and simulated in all their multiplicity of sectors and scales, of cause and effect. This paper attempts to...