This guide addresses the variety of infrastructural investments that are likely to provide the highest value for improving the performance of Irrigation &Drainage (I&D) as part of the efforts to innovate and modernize. Boosting the performance of I&D schemes requires attention to both on- and off-farm aspects. Enhancement of on-farm irrigation management is dependent upon a reliable and flexible water supply to fields. Off-farm systems require strategic and coordinated development to ensure that all parts work together as a unit (as opposed to focusing on individual structures or technologies). This guide was written to document the process of Innovation & Modernization (I&M) in I&D and the wide range of technological improvements that could help energize the irrigated agricultural sector globally. In a world where fresh water is increasingly a scarce commodity, a modernized irrigation sector could help respond to current and emerging water challenges and market opportunities, while adding economic, social, and environmental value. The guide's audience includes World Bank task teams, irrigation service providers and scheme operators, stakeholders in government, and various other decision-makers, such as irrigation and agriculture agencies and development organizations, as well as irrigating farmers and their organizations. The guide also provides an entry point into a detailed repertoire of technological I&M solutions organized in a series of technical fiches, attachments, and country case studies.