REQ42 is all you need to successfully manage requirements in an agile world. Scrum calls the role that is responsible for good requirements engineering „product owner“ and we follow this suggestion.
As a product owner your five key tasks are depicted in the following diagram. Note that there is no sequence for these five essential activities – quite on the contrary: they should be performed in a highly iterative way.
In an agile world the development process (sketched above) is less important compared to results. So as an overlay on the five key tasks of a product owner the next picture shows the key artifacts that are created and maintained over time. We use a color code for the artifacts: green indicates artifacts that are normally considered to be requirements artifacts. Red is for artifacts normally considered to be management artifacts. Since a product owner is a combination of manager and requirements engineer (or business analyst) he or she has to deal with all green and red artifacts.
The development team(s) will iteratively create product increments based on the priorities defined by the product owner. Artifacts of the development team are shown in blue. At the end of each iteration the product owner has to check and accept (or reject) this product increment.
Note that the product owner has more to do than just maintain the backlog of functional requirements!
