From time immemorial, people have been managing rain. The availability of water and water sources determined where people would be able to live. Adequate rainfall decided on the quality of agriculture. Technical advances and finance may have enabled societies to inhabit big cities and expand agriculture into dry areas, but only because of the resource rain provided through the water cycle. Due to population growth, pollution, and climate change, water scarcity will be one of the most critical problems all around the world in the next 15 years. Today, around 10% of the world’s population lacks a proper water supply service. Harvesting rainwater and using it for drinking, domestic, industrial, and agricultural uses will help to supply quality water to urban and rural populations. Divided into four sections, basic concepts, narratives of RWH, programs implemented by diverse sectors of society, and notable cases, the book summarizes experiences from 14 different countries all around the globe, developed and developing countries, urban and rural areas. The subject of this book is related to the promotion of different international rainwater experiences that provides sustainable water services and climate resilience, including technical aspects and socio-cultural and policy affairs. This book was written for all people interested in sustainable rainwater management. Students, people just starting in the subject, and experts will find this book interesting as it creates an overview of rainwater harvesting practice and technology all around the world. We encourage all readers to read these stories and arguments at your leisure. Some many ideas and techniques can be picked up and applicable for serving the last 10% that is waiting for water security and proper water service.