The initiating phase of an IT project requires careful attention to several crucial elements of the project planning process. Of course, requirements drive the entire development effort of an IT project, and hence deriving a set of correct, unambiguous, and complete IT project requirements is imperative. But there are three other important elements that also have direct impact on a project's success, namely assumptions, constraints, and risks. Each of these elements must be taken into account in a robust project plan. Assumptions are things that we believe to be true and which we therefore build into the project plan. Constraints are things that we know to be true and which must be accounted for in the plan so that we can work around them. And risks are factors that we are aware of but whose occurrence is uncertain. These factors may or may not happen, but a good project plan will be include accommodations for the most important of these, so that if they do in fact occur their impact on the project's schedule and budget will as minimal as possible. This book explores the definitions of these various elements, and how they should be included in the overall project plan. More specifically, practical tools and techniques are offered for identifying, assessing, and prioritizing such factors, with examples provided demonstrating how these tools and techniques can help make the project planning process more reliable and robust.