Real Property
Estates and future interests
Fee simple absolute, life estate, and defeasible fees (fee simple determinable with possibility of reverter; fee simple subject to condition subsequent with right of entry; fee simple subject to executory limitation). Remainders are vested or contingent. The Rule Against Perpetuities voids interests that might vest more than 21 years after a life in being; it reaches contingent remainders, executory interests, and vested remainders subject to open.
Concurrent ownership and leases
Tenancy in common has no survivorship; joint tenancy requires the four unities and carries survivorship; tenancy by the entirety requires marriage. Leaseholds: term of years, periodic, at will, at sufferance. The implied covenant of quiet enjoyment supports constructive eviction; the implied warranty of habitability is nonwaivable in residential leases.
Servitudes
Easements may be express, implied, by necessity, or by prescription; termination by merger, release, abandonment, or estoppel. Real covenants require writing, intent, touch and concern, and horizontal and vertical privity; equitable servitudes require notice and support injunctive relief.
Recording and financing
Race, notice, and race-notice statutes determine priority; the shelter rule protects a transferee from a bona fide purchaser. Mortgage priority, foreclosure, deficiency judgments, and redemption are recurring issues.
Worked example
O conveys to A for life, then to A's heirs. A has a life estate; the heirs have a contingent remainder that vests at A's death, so it is valid under the Rule Against Perpetuities.
Rule of thumb: chart the interests first, then test each future interest against the Rule.