This collection features four peer-reviewed literature reviews on integrated crop-livestock systems in agriculture. The first chapter reviews the use of integrated crop-livestock systems to achieve balance in organic animal farming. The chapter focusses primarily on the use of agroforestry systems, their potential environmental and economic benefits, as well as how they contribute to animal health and welfare. The second chapter examines the different state-of-the-art integrated crop-livestock systems in various eco-regions worldwide under Conservation Agriculture. As a world leader in the adoption of integrated crop-livestock systems, a substantial part of the chapter is dedicated to the research and adoption of these systems in Brazil. The third chapter illustrates how crop-livestock systems contribute to improving global food security and diversifying the diets of smallholder livelihoods. The chapter explores the climate resilience of these systems and the mitigation strategies developed and implemented by farmers to deal with climate variability. The final chapter discusses the development of whole-farm system models to understand the complexity of integrated crop-livestock systems. The chapter assesses the key processes governing interactions between farm components and provides two examples of common whole-farm model applications from contrasting environments to demonstrate this.