“an agreement free from vitiating factors such as mistake or misrepresentation and constituted by the unconditional acceptance of an outstanding offer involving a reasonably precise set of terms between two or more contractually competent parties who intend to create mutual and reciprocal rights and duties that may be the subject of judicial sanction if they are expressed in any required form， are free from the taint of illegality or immorality and are not subsequently discharged by law， by agreement， by breach or by sufficient supervening circumstances.”
Another clarification is in order. The deion given in this documentis indicative of the common law only. In many jurisdictions， laws have been implemented which directly alter the common law. For example， the United States of America has a Uniform Commercial Code which codifies much of the contract common law， but also changes much of it. The contract common law still applies in the USA but only to the extent that it has not been changed by the Uniform Commercial Code or， in other words， hardly at all！ In Australia， Canada， England and New Zealand， laws have been enacted to change the rules of contract common law in certain areas. For example， contract common law recognizes all contracts whether they are written or verbal. But a Statute of Fraud has been adopted in many common law countries which requires a written document for some contracts （ e.g. land contracts） . Consumer protection laws are in place in many jurisdictions as well. Therefore， what follows is the general rule of common law which applies only to the extent that it has not been changed by specific laws. Therefore， those readers with a real legal problem should be careful to additional research in their town jurisdiction to verify to what extent， if any， statutes have altered the following summary of contract common law. Note also that case names may have been shortened.
Contract law has come to us from common law and it is said thatit is an offspring of tort law. Both contracts and torts give rise to obligations. But tort obligations （ i.e. the obligation to indemnify for your negligence） are imposed by the law； it is not normally a choice one makes. Contracts， on the other hand， are a vehicle by which persons voluntarily create obligations upon themselves.