The product is a lot of 4 Warhammer 40,000 Codex books focusing on the Tau Empire, Eldar, Blood Angels, and Space Marines armies. Published by Games Workshop, these English-language books are essential resources for players of Warhammer 40K. The Codex series provides detailed information on each army's units, strengths, and strategies, making them invaluable tools for anyone looking to master their chosen faction in the Warhammer 40K universe.