Eco's library contained 30,000 books and tended to separate visitors into two categories: 'those who react with 'Wow! Signore professore dottore Eco, what a library you have! How many of these books have you read?' and the others — a very small minority — who get the point that a private library is not an ego-boosting appendage but a research tool. Read books are far less valuable than unread ones." By that measure, Eco might have amassed an even more valuable library than his fans would assume.