I should check if there's any new information post-July 2024. Wait, my knowledge is current up to July 2024, so if the user is asking now in 2024, there might be something new. But I don't have access to current data. So the safest approach is to inform the user that a third book hasn't been officially released as of July 2024. Also, caution them about PDF versions, which might be pirated copies. Emphasize the importance of supporting the author by purchasing official copies. Provide a summary of the existing books, discuss the user's confusion, mention the availability of PDFs but warn against illegal downloads, and suggest looking for the author's announcements for updates.