In this introductory chapter, we aspire to offer a comprehensive yet complete roadmap of the concept and content of the much used but not quite appropriately perceived term of sustainability economics. Interestingly, there is not a formal and universally accepted definition as the field is considered as a relative science and thus requires an interdisciplinary approach to be studied. However, through indicative yet recent literature, we offer an insight on the state of the art in order to relate to its core meaning. A historical background is also outlined as understanding the foundations is crucial. Elements of Economic Theory serves as means to bridge the past and current trends on how theories have evolved to understand what is necessary not only to achieve economic growth in numbers but also to ensure well-being and prosperity for the current and future generations.