Haha yeah, hmm, we can only utilize free API's such as wikipedia, so there's some inconsistencies all over the place. For anime and manga we use another API which keeps going down at times. If we were to pay for it, the cheapest option would be TMDB for $150/month which we're not really in a position to afford atm as the project has no revenue generation. :D

If it's not finding books at all I can take a look to see if something's blocking it.