Complex sentence: In 1939, the American Law Institute issued the Restatement of Torts, containing a summary of trade secret laws across states, which served as the primary resource until the latter part of the century.
Split into simpler sentences: In 1939, the American Law Institute issued the Restatement of Torts, containing a summary of trade secret law as it then existed. That summary served as the primary resource until the latter part of the century.