A series of rulings by multiple U.S. federal courts, including those in California, have established that training artificial intelligence (AI) models using copyrighted books without authors' permission constitutes fair use under copyright law. These decisions, notably involving Meta Platforms Inc. and Anthropic PBC, mark a developing legal precedent that permits the use of legally purchased books for AI training purposes without requiring explicit author consent. Courts have compared AI training to human learning through reading, emphasizing the transformative nature of this use. However, some rulings have also introduced new limits on the use of copyrighted materials, reflecting ongoing judicial debate and uncertainty. Meta's victory in these cases provides a potential roadmap for future defendants, though it remains unclear how authors might leverage these rulings. The evolving legal landscape is influencing industries beyond technology, including healthcare and legal services, where AI's role is expanding but also raising questions about intellectual property and liability.