Large software systems evolve because of the need to extend their functionality by adding new features or modifying existing ones. Release planning for such systems can be extremely challenging. There are both business and technical perspectives to this challenge. From a business perspective, new feature requests originate from stakeholders with diverse (and often conflicting) business interests, who all want their needs to be met, in spite of resource, schedule and other project constraints. From a technical perspective, incorporating a new feature into an existing software system, without breaking old features, can be a tough balancing act. This book discusses a novel and rigorous decision support technique known as SoRPES that addresses these two perspectives. The work provides a theoretical foundation for, and a novel formulation of, release planning as a multi-objective optimization problem. Using results from empirical validation studies conducted on real-world projects, the book presents software practitioners with a useful tool to generate release plans that are often more optimal and more practical than could be obtained by existing techniques.