There is no perfect 'Krag Book', however, these four books have different coverage and strengths.

For someone new to Krags and limited with 'library funds', I would suggest buying in this sequence. FWIW:

1. Joe Poyer's book ($20), "The American Krag Rifle and Carbine". It has lots of information and very good photographs. It can help one avoid easy mistakes.

[I have found some mistakes in the text and captions. His system of 'Types', for variations in parts, is not official nomenclature and the illusion of serial numbers, having precise known manufacture dates, has angered or irritated some individuals].

The book is an inexpensive collector's guide. It is convenient to take to gun shows and on trips. You can learn much, write in it, make notes and not feel guilty.

2. Franklin Mallory's book (about $100 to $200 used), "The Krag Rifle Story", 2nd edition.

Get the 2nd edition! Improved paper and format, over earlier edition, more content, and Krag SRS data.

3. Brophy's book (about $125 used), "The Krag Rifle". The book has better paper and picture quality than Mallory's. It also shows improved coverage of Norwegian and Danish Krags. Brophy's information is sometimes different than Mallory's. It is helpful to contrast the two books.

4. Joe Farmer's self published book, "Farmers Notes, Volume 6, Part 1: US Military Krags". (Ordering information and description is in KCA Classifieds).

(I have not seen or read it, yet. I easily made an enemy of the author and he blames me for his leaving the KCA Forum).

Trusted and experienced KCA friends have praised the work.