No invitation I can recall has caused me as much pleasure as Werner's letter inviting me to participate in this celebration of Musgrave's ninetieth birthday. I am confident that all who are participating in this event share a similar feeling. We all recognize in Richard Musgrave a combination of quite extraordinary personal and intellectual integrity and creativity, leavened with broad cultural sophistication, and seasoned with charm at once gruff and warm. He is one of those rare people who elicit both respect and affection and who display both dignity and warmth. We have all been touched personally, or emotionally by a life that spans and has surmounted the catastrophic, yet miraculous, century just ended. Although I never took a course from him, Musgrave was my teacher through his writings, as he was to every public finance economist who passed through graduate school for the two decades from 1960 to 1980. We are all honored by the privilege of celebrating his life with him. Let me amend that we are all honored by being privileged to celebrate the lives of Richard and Peggy with them, for much of his work is the work of the Musgraves. This invitation caused me, as it did many others, to try to take stock of his intellectual contributions and to assess, at a more personal level, what they mean to me. Doing so is not easy for two reasons. The contributions are numerous, but the greater challenge lies elsewhere. The intellectual constructs that he pioneered are now so much a part of our thinking that it is hard now to recover our pre Musgrave mindsets, a necessary step in measuring his contributions. Doing so underscored the fact that, as others have noted. Various sections of that book provoked different thoughts. An economy is best understood when we study its components or sectors. Sectoral classification can be done on the basis of several criteria. In this chapter, three types of classifications are discussed. You can create a discussion about these types by taking examples familiar to the students and relate them to their daily life. It is important to emphasise the changing roles of sectors. This can be highlighted further by drawing attention of the students to the rapid growth of service sector. While elaborating the ideas provided in the chapter, the students may need to be familiarised with a few fundamental concepts such as Gross Domestic Product, Employment etc. Since the students may find this difficult to understand, it is necessary to explain to them through examples