The Supreme Court’s 1960 Steelworker Trilogy decisions established that arbitration was the quid pro quo for the collective bargaining agreement’s no-strike provisions, and directed that judicial deference. In this Chapter, Professor Gould surveys the judicial history that preceded the Trilogy and the subsequent application and expansion of the Trilogy principles (including its recent exansion – in Pyett – to rulings on external law); the duty to bargain when the employer changes form, ownership, or identity; the judicial review of awards; and the jurisprudential relationship between grievance and interest arbitration.