This new edition describes current best practices in requirements engineering with a focus primarily on software systems but also on systems that may contain other elements such as hardware or people. The text consists of original papers, written by experts in the field, plus revisions of papers from the first edition. The book begins with an introduction to current issues and the basic terminology of the software requirements engineering process. The text covers the five phases of software requirements engineering -- elicitation, analysis, specification, verification, and management -- that need to be performed to reduce the chance of software failure. The chapters look at the science and discipline that concern establishing and documenting software requirements. The book covers the process through which developers' and users' discover, review, articulate, and understand the users' needs and the constraints on the software and development activity. It analyzes the users' needs to arrive at a definition of their software requirements. In addition, the papers examine software requirements and the need to clearly document and precisely record each requirement. It also looks at verification to ensure that the software requirements specifications are in compliance with the system requirements and conforms to document standards. The last phase addressed by the book is software requirements management including planning and controlling of all these activities.