Buzzfeed has a nice article on MSG by John Mahoney. Emphasis is on umami taste, DIY MSG, and the moral panic associated with the food additive. It’s worth noting that like many other crucial food flavors, MSG is the product of a bacterial process:
Today, MSG is manufactured commercially by fermentation that is more or less the same as what’s happening in the Momofuku R&D lab. In factories around the world, a bacterium known as Corynebacterium glutamicum (so named for its prized waste products) is fed plant glucose (corn, beets, wheat). As it eats, it releases glutamic acid. The resulting fermented product is filtered and centrifuged to isolate the glutamic acid and remove by-products and impurities, it’s crystallized, and out comes MSG.