I would use reasonable judgment. No, you mustn't list every book - but you shouldn't write "Personal Items $5000" either. Group like things together, such as "Books $250", etc. Remember that you must be able to prove ownership (and cost) of items to make the claim, so you don't want to be so broad as to make that complicated - nor so specific that it's impossible to get through the form. Use sensible categories, breaking out any individual piece that has a significant value.