Rent control legislation and administration in the United States and Canada have emerged through a complex process of trial and error, initiative and challenge, innovation and marginal change. Rent control legislation differs considerably depending upon the author of the legislation; the setting; and the legal constraints. Rent control legislation may not necessarily cover all tenants. Although rent control has not been means-tested, certain classes of rental housing have often been exempted from regulation. Vacancy decontrol notwithstanding, usually the single most contentious issue in rent control legislation is the setting of controlled rent levels. Under the return on value standard, the landlord is entitled to rents adequate to cover operating expenses and yield a specified return on the “value” of the building. The legislation that enables rent control also specifies how it is to be governed and administered, leaving here, too, much room for variation.