AI and the Quantity and Quality of Creative Products: Have LLMs Boosted Creation of Valuable Books?

With the diffusion of LLMs between 2022 and 2025, new book releases have tripled, raising a question of AI's impact on book quality. We develop a ratings-based usage measure that is comparable across book release vintages, and we find that the vintages from the AI influx period have lower average quality. Yet, the top 1,000 monthly releases per category - albeit not the top 100 - have higher quality than before; and the effect is larger in categories with faster growth in new titles. Authors entering since the LLM influx produce predominantly low-quality work; and the higher-quality output of pre-LLM authors entrants has risen. A nested logit calibration shows that LLM-enhanced book production could, in steady state, raise the surplus that consumers derive from book markets by a quarter to a half.