While impossibility, frustration of purpose, and mutual mistake can be defenses to breach of contract, a unilateral mistake generally does not excuse performance unless the other party knew or had reason to know of the mistake.
While offer, acceptance, and consideration are essential elements of a valid contract, notarization is generally not required unless specified by statute for certain types of contracts.
The rule against perpetuities is a common law rule that limits the duration of future interests in property, typically to no later than 21 years after the death of a life in being at the creation of the interest.
Present sense impression is a recognized exception to the hearsay rule, allowing statements describing or explaining an event made while or immediately after perceiving it.
Res ipsa loquitur is a doctrine that allows a jury to infer negligence from the mere fact that an accident occurred, when the accident is of a type that doesn't ordinarily happen without negligence.
