Contract law spans many specialty areas of law. A paralegal must have a working knowledge of contract law to be effective in the fields of real estate law, family law, corporate law, and many other fields. Paralegals are often called on to review contracts to determine the rights and duties of a client under an existing contract. They may be asked to interview a client or witnesses to ascertain the amount and type of damages resulting from a breach of contract. Antenuptial agreements, real estate purchase agreements, and stock buy-sell agreements are all forms of contract. Litigation over product liability claims requires knowledge of the warranty provisions of Article 2 of the UCC. A paralegal is not truly well educated without a command of the basic principles of contract law.