One of Lucien's features is the ability to read certain books out loud to you. To use this feature, one of the compatible books must be present in his or your inventory. If so, a "Read to me" dialogue option will appear after you select "I need you to do something." Recording these is a slow process, so currently the list of compatible books is very small. I'll be expanding it over time in future updates, though, and updating this article as I do so.