Eukaryotic organelles are known to be in close contact with one another. These contact sites allow the organelles to communicate and exchange small molecules, such as lipids. In this course, we will explore current literature on the mechanisms of Membrane Contact Sites (MCS) formation, the nature of small molecule exchange between organelles, and its contribution to cell homeostasis and viability. We will also examine how some pathogens can commandeer MCS for their own propagation. Limitations of current approaches and novel methodologies to address MCS function will also be addressed.