Agile development has its origins and roots in practice rather than academia. Hence, in this research, we go to the practitioners' world to explore what they want to know about Agile development. We conducted our study using a multi-methodological approach, a combination of a survey and an interpretive case study. We learned that Agile development is yet to reach a mature phase with: a) relatively limited numbers of experienced Agile practitioners; b) a large number of software developers who were trained in plan-based Waterfall development trying to transition to Agile; c) some companies and practitioners continuing to be skeptical of the benefits of Agile development over plan-based development; and d) tools in the process of being developed to support Agile development. Based on those factors, we learned that practitioners are wanting to find answers to the following questions: a) What should good Agile practitioners and teams know and do? b) How to train developers and teams to become good Agile practitioners? c) How to transition from plan-driven Waterfall development to Agile development? d) What tools are available to practice Agile development? How to use them to support Agile practices? The following are the answers we derived from our interpretive case study for the above four questions: a) Good Agile practitioners define their job in terms of the client's mission; they don't define their jobs as analysts, designers, programmers, testers, or project managers; b) For training, Agile practices such as test-driven development and continuous integration are best understood not in theory but by the act of doing; for organizational adoption of Agile development, Agile practices should be used not only in software development but encouraged in all functional areas; c) The best way to introduce a plan-based Waterfall practitioner to Agile is to have him think of Agile in terms of something familiar, as a series of mini-waterfalls that have very quick iterations; d) Simple tools, even non-software tools, that help manage Agile practices intuitively are preferable to complex Agile management software.