If you have any interest in Krag rifles and carbines either historically or as a budding collector, I would recommend getting both Brophy's and Mallory's books on Krags for your library. Much more dependable research in them and they compliment each other. It has been discussed that Poyer's book is a good place to start but anything further requires Brophy's and/or Mallory's books.

If you get really serious and want an ultimate Krag research experience, get Joe Farmer's book. It's packed full of recent research and an interesting read from his unique experience as a collector.

You can always read old posts on this site and look at the thousands of pictures in them to learn a ton about Krags also.

Good luck!