This chapter is intended to present some basic definitions and approaches of sustainability. Also, it aims to critique the current economic model which failed people, nature and economy. The argument is that the current market economy is not telling us the ecological truth and that GNP is not the right metrics to measure the heath and wealth of nations. The chapter describes the pitfalls and shortcomings of the prevailing economic model that is based on growth and overconsumption and that is characterised by huge gap between the rich and the poor, overconsumption, pollution and climate risks.