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http://en.wikipedia.org/wiki/Bailment

General

Bailment is distinguished from a contract of sale or a gift of property, as it only involves the transfer of possession and not its ownership. To create a bailment, the bailee must both intend to possess, and actually physically possess, the bailable chattel. Bailment is a typical common law concept although similar concepts exists in civil law (Spain- Depósito).

In addition, unlike a lease or rental, where ownership remains with the lessor but the lessee is allowed to use the property, the bailee is generally not entitled to the use of the property while it is in his possession.
A common example of bailment is leaving your car with a valet. Leaving your car in an unattended parking garage is

typically a license rather than a bailment, as the car park's intent to possess your car cannot be shown. However, bailments arise in many other situations, including terminated leases of property, warehousing (including store-it-yourself) or in carriage of goods.