Contract and Related Obligation, Ninth Edition, focuses on the rules and principles of contract law, as well as the lawyer's role in planning and drafting contracts. Chapter One helps distinguish the book from others. It sets the stage by following a contract case from the agreement stage, to a breakdown in the parties’ relationship, to a lawsuit, to a decision in the trial court, and to the final appellate court opinion. This introduction includes supporting materials, including the parties’ agreement, a correspondence from the lawyer to the client, the complaint, a motion to dismiss, the answer, the trial judge's charge to the jury, the special verdict form, the trial judge's decision on motions after the verdict, and the appellate court opinion. These materials help students understand where cases come from and lawyers’ various roles, including planning, negotiating, counseling, drafting, as well as litigating. Following Chapter One, the Ninth Edition offers comprehensive coverage of contract law theories of obligation, including bargain, promissory estoppel, unjust enrichment, and tort arising in the contract setting. This edition also includes new cases and secondary sources on developing issues of contract law, including enforcement of digital contracts, the role of artificial intelligence in contract interpretation, and the new Restatement of Consumer Contracts. The new edition supplements many of the chapters with new excerpts from important articles drawn from the authors’ own scholarship as well as cutting edge papers in the field, especially many that emerge from the law and social science and law and psychology traditions. New additions include material on promissory estoppel, Statute of Frauds, damages, unjust enrichment, contract modification, contract interpretation, good faith, duress, misrepresentation, waiver, anticipatory repudiation, mistake, third party beneficiaries, and assignment and delegation. Some of these additi