A borrower of money, or one owing a debt may, for the purpose of securing payment of the amount due the lender or creditor, execute an instrument known as a mortgage. This instrument purports to transfer to the creditor the title to specific real property. As the transfer, from the point of view of the law in New York and many other States, is merely conditional, becoming null and void upon payment of the debt, the mortgage does no more than create a specific lien on the property. Because of the importance of mortgages in the real estate business a separate chapter has been devoted to them.