From the Preface:
The Aṭṭhakavagga is the fourth chapter of an ancient collection of Buddhist scriptures known as the Sutta Nipāta. Although it is only a single chapter of a larger work, there is good evidence suggesting that the Aṭṭhakavagga existed in its own right prior to the compilation of the Sutta Nipāta, and that it was much better known and more influential in ancient times than it is today. This lapse into relative obscurity is unfortunate, as the Aṭṭhakavagga contains invaluable information for anyone wishing to better understand the earliest teachings of Buddhism, and also for anyone seeking the way of wisdom.
http://pathpress.wordpress.com/2012/06/ ... anslation/