Lost, mislaid, and abandoned property are categories of the common law of property which deals with personal property or chattel which has left the possession of its rightful owner without having directly entered the possession of another person. Property can be considered lost, mislaid or abandoned depending on the circumstances under which it is found by the next party who obtains its possession.
There is an old saying that possession is nine-tenths of the law, perhaps dating back centuries. This means that in most cases, the possessor of a piece of property is its rightful owner without evidence to the contrary. More colloquially, this may be called finders, keepers. The contradiction to this principle is theft by finding, which may occur if conversion occurs after finding someone else's property.
The rights of a finder of such property are determined in part by the status in which it is found. Because these classifications have developed under the common law of England, they turn on nuanced distinctions. The general rule attaching to the three types of property may be summarized as: A finder of property acquires no rights in mislaid property, is entitled to possession of lost property against everyone except the true owner, and is entitled to keep abandoned property. This rule varies by jurisdiction.
Property is generally deemed to have been lost if it is found in a place where the true owner likely did not intend to set it down, and where it is not likely to be found by the true owner. At common law, the finder of a lost item could claim the right to possess the item against any person except the true owner or any previous possessors.
The underlying policy goals to these distinctions are to (hopefully) see that the property is returned to its true original owner, or "title owner." Most jurisdictions have now enacted statutes requiring that the finder of lost property turn it in to the proper authorities; if the true owner does not arrive to claim the property within a certain period of time, the property is returned to the finder as his own, or is disposed of. In Britain, many public businesses have a dedicated Lost Property Office (LPO), which in the United States would be called a lost and found.