In this article, we’ve discussed how a security interest is a property interest created by agreement or by operation of law over assets to secure the performance of an obligation. The obligation in question is usually the obligation to make payment on a debt. With respect to real property, we looked at four main security interests. Those security interests were: (i) mortgages, (ii) deeds of trust, (iii) installment land contracts, and (iv) sale-leasebacks. In this article, we’ve discussed each one of those security interests, and we’ve used some real world examples to flesh out some of the more complex concepts.