substitutes. But they are substitutes. As such, there are no pure monopolies in the real world. Monopoly market structures can be thought of in one of two ways. One is as an abstract, theoretical model of a market containing a single seller. The other is as a realistic market in which one firm more or less dominates the market. The real world does not contain any theoretical, abstract "pure" monopoly markets. Neither does the real world contain other representations of idealized abstractions, such as a "dimensionless point" or a "utility-maximizing consumer." However, in the real world, which contains every color EXCEPT absolute black and absolute white, there are also varying shades of monopoly. Real world monopolies are not "pure." They are NOT absolutely the ONLY firm in a market. They do NOT produce a good that has absolutely NO substitutes. But some real world firms sort of, almost, kind of, come close to the theoretical ideal of monopoly ]