Macroautophagy (autophagy) meaning self-eating is an evolutionary conserved intracellular degradation pathway, during which autophagosomes envelop bulk cytosol, unwanted or damaged organelles and misfolded proteins to handle them to the lysosomes for breakdown. There are many types of autophagy, which differ mainly in the site of cargo sequestration and in the type of cargo itself. The process of autophagy is a model in which autophagic vesicles develop into mature degradative autophagolysosomes in a series of distinguished steps namely: initiation, nucleation, expansion, maturation then finally degradation. The discovery of definitive biological markers for autophagy by the Japanese, Nobel Prize-awarded cell biologist Yoshinori Ohsumi and the advances in visualizing techniques enabled further insight of this vital process. Autophagy takes place at a low basal level constitutively, and can be potently induced by various types of stress conditions, such as starvation, hypoxia, pathogen invasion, and exercise. The functional relationship between apoptosis and autophagy is complex. Under certain circumstances, autophagy constitutes a stress adaptation that avoids cell death (and suppresses apoptosis), whereas in other cellular events, it constitutes an alternative cell-death pathway. Recently, autophagy dysfunction is linked to severe diseases such as neurodegeneration and cancer. Control of autophagy promises to facilitate the development of therapeutic and preventive measures for these morbid diseases for the well-being of mankind.