This report focuses on how we achieve water sustainability over long timescales - decades, even centuries from now. These timescales are important and relevant to our decisions about planning, infrastructure, and institutions today. Many of the methods we use to manage water, directly or indirectly, commit us to future decision pathways and restrict us from making other, alternative decisions. Across the first four chapters, this report describes the challenges of including climate change in water management decision-making and provides an overview of current practices in the adaptation field. After considering the pros and cons of these practices, the book concludes with a framework for an adaptation approach supported by Alliance for Global Water Adaptation (AGWA).