A comic-book collector signs a written contract with a man who has inherited a large collection. The collector asks to include a rare Batman issue by email; the contract lists the included comics but not the Batman issue. The Batman issue is missing from the shipment. The collector sues; the court rules based on the parol-evidence rule. Why?

• A. Yes, parol evidence may be used to show Batman was included.
• B. No, the parol-evidence rule bars extrinsic terms when the contract says it is the complete and final agreement.
• C. Yes, because emails are always admissible to modify a contract.
• D. No, because extrinsic evidence is always allowed for interpretation.

Answer: (B)

The key idea is that a written contract can be treated as the final and complete expression of the agreement. When a contract includes an integration or completeness clause—stating it is the whole deal—parol evidence rules prevent adding or varying terms with outside writings, like emails. Here, the contract lists the included comics and omits the Batman issue, and it is framed as the complete agreement. An email attempting to add the Batman issue is extrinsic to the written terms, so it can’t modify the contract. Only a separate signed modification (or another recognized exception) could change what was agreed. That’s why the court relies on the parol-evidence rule in this scenario.