In what circumstances can a person be liable to a pecuniary remedy for conduct which has not caused the plaintiff any harm? This question lies at the heart of the present topic, in which the plaintiff seeks to disgorge a benefit acquired by the defendant through the latter's wrongful act, even though the wrong has not actually caused him loss or injury. Consider, for example, a trespasser who has benefited by using a track across the plaintiff's land without reducing the value of the land; the plaintiff, who might never have been willing to consent to such use of his land, now seeks payment as if his permission for that user had been sought at a price. In terms of “unjust enrichment,“ the plaintiff's claim is that the defendant's enrichment is “ “unjust” by virtue of the wrong committed, without showing that the enrichment is at his expense.