This edition of Agua Series Brazil presents an analysis on projects of water transference between hydrographic basins. Projects implemented in Brazil and in diverse parts of the world are discussed, and examples of the aspects determining successes and failures are given. The objective is to present suggestions on how to improve the planning and the implementation of complex water transfer projects. After the introductory chapter, chapters 2 and 3 discourse on some relevant international and national experience in transfer of great volumes of water between basins. Later, in chapter 4, the issues with water resources in the Northeast region and the proposal of the PISF (Project of Integration of the San Francisco) are analyzed with the objective of conceiving the alternatives to improve service and the use of the water resources of the region. Commentary on a series of common aspects that have characterized the success of -- or the difficulties faced by -- some projects is organized in the form of lessons learned, presented in chapter 5. The conclusions are presented in chapter 6.