If you are looking for a great way to increase your knowledge and heart for the nations, check out Operation World. This one volume covers a brief overview of each country in the world, including the spiritual climate, unreached peoples living in each country and brief prayer points.
They offer a sample 60 day prayer guide on a select number of countries that will allow you to begin to engage in prayer for every tribe, people and language. You can pick up the entire volume on Amazon, by following this link.
The Operation World website, with a quick link to the 60 day prayer guide can be found here.
Written by Ryan Martin