Army of Two: Prima Official Game Guide

The guide for Army of Two, while not strictly necessary, is very useful. It offers good strategies for tough sections of the game and helps identify secondary objectives and hidden items to collect. It also offers a complete guide of all the weapons which can be purchased and how all the various upgrades affect their stats and performance in the field. Not too much else to say about it, it is a good guide which provides useful information to help with the game and does so in a fairly concise and easy to read way. Not strictly needed, but a good thing to have if you're having trouble.