Decision makers and the public are in need of information to guide their decisions about how to strengthen health services. This book pulls together available evidence concerning strategies to improve health services delivery in low- and middle-income countries (LMICs), using current methods to assemble a knowledge base and analyze the findings. It describes the results of reviews of such strategies, and how such strategies can produce gains for the poor. This type of information is intended to help decision makers in LMICs learn from others and from their own experiences, so that they may develop and implement strategies that will improve health services in their own setting. The book provides some suggestions for what works and how to improve implementation, as the evidence does not hold up for 'blueprint' planning. It finds that there are many ways that can succeed in improving health services. But not nearly enough attention has been paid to demonstrating how to improve services for the poor. Approaches that ask difficult questions, use information intelligently, and involve key stakeholders and institutions are critical to 'learning and doing' practices that underlie successful implementation of health services.