The Source Separation model will be easier to explain if the mechanics of a “cocktail party” are first described. The cocktail party is an easily understood example of where the Source Separation model can be applied. There are many other applications where the Source Separation model is appropriate. At a cocktail party there are partygoers or speakers holding conversations while at the same time there are microphones recording or observing the speakers also called underlying sources. The cocktail party is illustrated in adapted Figure 1.1. Partygoers, speakers, and sources will be used interchangeably as will be recorded and observed. The cocktail party will be returned to often when describing new concepts or material.