title_body: Where are books downloaded from Amazon Kindle app stored in Android?
upvoted_answer: The path should be something like "mnt/sdcard/android/data/com.amazon.kindle/files"
  
  Just navigate to it with file manager of choice.
  
  Download history won't be of help. 
  App and it's data are usually stored in separate places.
  
  Many file managers allow searching for a file, but most often then not it's a pain in the arse to do so. (With Root Browser, atleast)