765 ILCS 730/1

That the purpose of this Act is to regulate the prevalent practice of making or using written leases of real estate, which, because of concessions to the lessees, do not truly state the real net rent being paid, it being recognized that such practice can be, and frequently is, used to mislead prospective purchasers and lessees, and lenders of money on the security of such real estate, into a belief that the rental value or market value thereof is greater than it really is.