Systems approaches are excellent in integrating insights in the physical, chemical, Systemsapproachesareexcellentinintegratinginsightsinthephysical,chemical, physiological and ecological processes that dictate the behaviour of living systems, of physiologicalandecologicalprocessesthatdictatethebehaviouroflivingsystems,of which which agro-ecosystems agro-ecosystems are are important importantones. ones. Furthermore, Furthermore, they theyhelp help to tobridge bridge the the gap gap between betweendetailed detailed process processoriented oriented studies studies and and higher higherintegration integration levels. levels. Systems Systems approaches approaches are are roughly roughlycategorized categorized in inthree three groups groups of of studies: studies: (i) (i) predictive predictive studies studies to to support support decision decision making making and and guide guide interventions, interventions, (ii) (ii) systems systemsanalysis analysis and and simulation simulation in inorder order to toget get insight insight and and understanding understandingof of the the functioning functioningof of (living) (living) systems, systems, and and (iii) (iii) explorative explorative studies studies to to investigate investigate possible possible options options for for development development and and trade trade offs offs of of aims, aims,objectives objectives and andconstraints. constraints. All All these these systems systems approaches approaches are are now nowwidely widely used used in inecological ecological systems systems including including agriculture, agriculture, and and applied appliedin in land landuse use planning. planning. This This book book is is an an introduction introduction to toone one of ofthe the major majorfields: fields: systems systems analysis analysis and and simula- simula- tion. tion.