If it is a professional bookstore, the clerk may be required to know some professional knowledge. For example, the clerk in a computer bookstore should at least know the name and purpose of each software.

However, most bookstore clerks don't need any special talents, they are enthusiastic and careful enough. Of course, the higher the quality, the more popular it is. If you can talk to readers about Rousseau or Heidegger … what are you doing in the bookstore?