In a monopolistic pricing setting where the buyer has quasi-linear preference and unit demand and the seller has private production cost, I introduce an informational monopolist who has the ability to design information structures between the buyer and the seller about the buyer's value, and then sell these information structures to the seller. I consider three environments that differ in the set of feasible information structures for the informational monopolist: The one where the buyer is fully informed and the informational monopolist can design and sell any information about the buyer's value to the seller; The one where both the buyer and the seller are initially uninformed and the informational monopolist can provide any information to the buyer and then charge the seller for this service; as well as the one where the informational monopolist is able to design any information structure between the buyer and the seller, subject to a constraint that the buyer must be better-informed. These three environments correspond to three leading examples: The sale of consumer data by data brokers, the sale of advertisements by agencies, and the design of online trading platforms. In each environment, I further consider two market regimes: One in which the informational monopolist can contract with the seller on product prices and one in which the informational monopolist cannot contract on prices. The main results consist of two parts. First, I completely characterize the revenue-maximizing mechanisms for the informational monopolist under each environment and each market regime. Using this characterization, I further show that in each of these environments, the market outcomes are equivalent under any optimal mechanisms and any market regime, which implies that the informational monopolist's ability to contract on price is irrelevant when he can design and sell information flexibly.